Jet jet device

Abstract

The present invention provides a microfluidic device (1) for jet ejection, where the microfluidic device (1) comprises a main chamber (100) defined by chamber walls (110), where the main chamber (100) is configured to contain a liquid (10), where the main chamber (100) has a chamber length (Lc) defined by a first chamber end (101) and a second chamber end (102) along a device longitudinal axis (AD), where the chamber length (Lc) is greater than the first chamber end (101) and the second chamber end (102). The first chamber tip (101) comprises a first chamber opening (1011) for jet injection from the main chamber (100); wherein the chamber wall (110) comprises a pattern (300) of a first surface material (111) and a second surface material (112), where the first surface material (111) has an equilibrium contact angle [theta] 1 > 90 DEG with respect to the liquid (10), and where the second surface material (112) has an equilibrium contact angle [theta] 2 with respect to the liquid (10), where [theta] 1-[theta] 2 > = 20 DEG; wherein the pattern (300) comprises areas (200) wherein the areas have area boundaries (205), and wherein a) the areas (200) comprise one of a first surface material (111) and a second surface material (112), and wherein b) at least 50% of the area boundaries (205) are in contact with the other of the first surface material (111) and the second surface material (112); wherein the chamber wall (110) has a wall surface area (Sw), and wherein the district (200) has a district surface area (SP), where 10 <-4 > < = SP / Sw < = 2 * 10 <-1 >.

Description

Technical Field

[0001] The present invention relates to a microfluidic device for jet ejection, an ejection system comprising the microfluidic device, and a method for ejecting a jet using the microfluidic device. Background Art

[0002] Microfluidic jet injection systems are known in the art. For example, WO2021152476A1 describes a method for ejecting a fluid jet onto a substrate, the method comprising: providing a nozzle filled with a fluid; placing a pulsed radiation fiber source inside the nozzle and in direct contact with the fluid, the fiber source comprising an optical fiber, wherein the fluid is configured to absorb at least a portion of the radiation; the method further comprising: generating bubbles inside the nozzle by absorbing pulses of pulsed radiation from a first portion of the fluid, thereby evaporating the fluid to form bubbles; through the action of the bubble expansion, pushing a second portion of the fluid from an opening at the end of the nozzle so that the end is directed toward the substrate, thereby achieving the ejection of the second portion of the fluid; and the pulse intensity is configured to be lower than the radiation induction threshold of the material contained in the fiber source.

[0003] US20080186356A1 describes a nozzle plate having a nozzle hole formed therethrough, wherein the nozzle hole is defined in the nozzle plate, and an inner surface of the nozzle plate includes a first lyophilic portion, a lyophobic portion, and a second lyophilic portion arranged in sequence from a side close to the nozzle opening, the first lyophilic portion and the second lyophilic portion having lyophilic properties, and the lyophobic portion having lyophobic properties.

[0004] US2022153028A1 describes a jet injection system comprising (i) a microfluidic device for jet ejection and (ii) a laser-based heating system, wherein: the microfluidic device comprises a main chamber defined by a chamber wall, the main chamber having a chamber height h selected from the range of 5-400 μm c , from 2h c -10h c The chamber width w is selected within the range c and a chamber length l defined by the first chamber end and the second chamber end c , wherein the second chamber end includes a first chamber opening for ejecting a jet from the main chamber, and wherein the main chamber is configured to contain a liquid; and the laser-based heating system is configured to provide laser radiation to one or more chamber walls and the liquid in the main chamber.

[0005] EP2388032A1 describes a device for generating at least one microfluidic jet, comprising at least one conduit segment, one end of which opens to the device environment. The device also includes at least one structure for forming a curved liquid surface in the at least one conduit segment, the curved liquid surface forming an interface between the liquid in the conduit segment and the environment at a certain position within the conduit segment. The curved liquid surface is at least partially concave when viewed from the end opening to the environment toward the interior of the conduit segment. The device includes at least one reservoir for storing liquid in fluid communication with the at least one conduit segment. The device also includes at least one device for delivering an energy pulse to the liquid in the at least one reservoir, the device being configured to generate a shock wave front that propagates to the curved liquid surface and causes at least the first stage of the jet to be ejected from the central portion of the curved liquid surface. Summary of the Invention

[0006] The present invention relates to a microfluidic injection system comprising a microfluidic device for generating a fluid jet. More specifically, the system is capable of controlling the jet in a manner that is not entirely dependent on the device geometry or input energy.

[0007] Microfluidic devices (also called "microfluidic platforms" or "microfluidic systems") encompass a wide range of devices related to the field of microfluidics. Microfluidics involves the behavior, control, and manipulation of fluids, typically involving very small volumes, such as μl, nl, pl, and fl. Microfluidic devices enable precise control and manipulation of fluids at micron to submicron scales.

[0008] Microfluidic injection technology offers an alternative to traditional injection methods, such as those using a needle. "Jet" is also referred to as "liquid jet" and "microfluidic jet." Microfluidic jets offer a method for injecting liquids into viscoelastic materials, such as the skin. In particular, microfluidic jets represent a promising alternative for transdermal drug delivery.

[0009] Vaccines and drugs are currently delivered using needle injection. However, this invasiveness is a limiting factor. Jet injectors are a promising alternative for transdermal drug delivery. Microfluidic devices used for jet injection rely on accelerating a liquid jet to a velocity sufficient to penetrate the target viscoelastic material. Conventional jet injectors may rely on a spring or gas reservoir to generate the jet. However, such devices may have limited control over injection parameters, such as volume and depth. Furthermore, they may require a nozzle to generate a jet fine enough to penetrate the target viscoelastic material.

[0010] Another key requirement for accurate and safe delivery of a liquid to a target viscoelastic material is jet stability, especially in applications such as drug delivery by micro-jet injection. Due to fluid instabilities such as Rayleigh-Plateau instability, a microfluidic jet can break up into smaller droplets with less inertia over time. In addition, the jet tail can slow down or wobble in different directions (i.e. the jet angle of ejection is not ideal). Both effects can reduce the penetration power of the jet and can lead to splashing and / or incomplete delivery. This can reduce the reproducibility and effectiveness of the microfluidic jet. In addition, splashing can contaminate the jet ejection system and / or the microfluidic device.

[0011] It is therefore an aspect of the present invention to provide a microfluidic device for jet ejection, which preferably further at least partially obviates one or more of the above-described drawbacks. It is an object of the present invention to overcome or ameliorate at least one of the disadvantages of the prior art, or to provide a useful alternative.

[0012] It is therefore an aspect of the present invention to provide a microfluidic device for jet ejection, which preferably further at least partially obviates one or more of the above-described drawbacks. It is an object of the present invention to overcome or ameliorate at least one of the disadvantages of the prior art, or to provide a useful alternative.

[0013] Thus, a first aspect of the present invention provides a microfluidic device for jet ejection. In embodiments, the microfluidic device can comprise a main chamber defined by a chamber wall. In particular, the main chamber can be configured to contain a liquid. In embodiments, along a device longitudinal axis (A D ), the main chamber can have a chamber length (L c ) defined by a first chamber end and a second chamber end. In embodiments, the first chamber end comprises a first chamber opening for jet ejection from the main chamber. In embodiments, the chamber wall can comprise a (surface) pattern of a first (repellent) surface material and a second (affine) surface material. In particular, the first surface material can have an equilibrium contact angle θ1> 90° to the liquid. In addition, the second surface material can in particular have an equilibrium contact angle θ2to the liquid. In embodiments, θ1— θ2≥ 20°. In embodiments, the (surface) pattern can comprise a (surface) patch. In particular, the patch can be a two-dimensional shape defined on a surface of the chamber wall. In embodiments, the patch can have a patch boundary. In particular, the patch can comprise one of the first surface material and the second surface material. More particularly, at least 50% of the patch boundary can be in contact with the other of the first surface material and the second surface material. In embodiments, the chamber wall can have a (wall) surface area (S w ). In particular, the (surface) patch can have a (patch) surface area (S P ). In embodiments, 10 —4 ≤ S P / S w ≤ 2*10 —1 .

[0013] Thus, in a specific embodiment, the present application provides a microfluidic device for jetting, wherein the microfluidic device comprises a main chamber defined by a chamber wall, wherein the main chamber is configured to hold a liquid, wherein along a device longitudinal axis (A D ), the main chamber has a chamber length (L c ) defined by a first chamber end and a second chamber end, wherein the first chamber end comprises a first chamber opening for jetting from the main chamber, wherein the chamber wall comprises a (surface) pattern of a first (repellent) surface material and a second (affine) surface material, wherein the first surface material has an equilibrium contact angle θ1> 90° to the liquid, and wherein the second surface material has an equilibrium contact angle θ2to the liquid, wherein θ1— θ2≥ 20°, wherein the (surface) pattern comprises (surface) patches, wherein the patches have patch boundaries, and wherein (a) the patches comprise one of the first surface material and the second surface material, and wherein (b) at least 50% of the patch boundaries are in contact with the other one of the first surface material and the second surface material, wherein the chamber wall has a (wall) surface area (S w ), wherein the (surface) patches have a (patch) surface area (S P ), wherein 10 —4 ≤ S P / S w ≤ 2*10 —1 .

[0014] Such a microfluidic device can produce a microfluidic jet with higher stability and reproducibility. In particular, the microfluidic device can comprise a heterogeneous surface chemistry to have a higher level of control over the liquid and the microfluidic jet. Furthermore, the chamber wall of the microfluidic device can have multiple regions with different affinity (or "affinity degree"; e.g. hydrophilic and repellent regions, or lipophilic and oleophobic regions) within the main chamber. Thus, at different locations within the main chamber, the attraction between the liquid and the chamber wall can be different. This can change the shape of the meniscus (liquid-gas interface) and create more complex meniscus shapes. Since the attraction of the liquid to the affine surface is larger, the capillary flow along the affine surface will typically be faster. Thus, the meniscus advances faster along the affine surface compared to the repellent surface. This enables to create interface lines from the affine region to the repellent region where the meniscus slows down (or its displacement is changed), thereby enabling to create a more reproducible filling level. Controlling the filling level is important for jetting, since the filling level can help to control the jet volume and can further help to control the jet velocity, thereby (also) helping to control the jet depth. Furthermore, the heterogeneous surface chemistry (also) can confine the tail to the same direction as the rest of the jet.

[0015] As mentioned above, the heterogeneous surface chemistry of the chamber wall can be provided by the configuration (consisting of the pattern) of the patches. In particular, the pattern can comprise two types of patches (i.e. patches having different shapes, orientations, compositions and materials).

[0016] In embodiments, the patches can (typically) be elongated. In further embodiments, the patches can be (i) configured perpendicular (or almost perpendicular) to the device longitudinal axis (A D ), or (ii) configured parallel (or almost parallel) to the device longitudinal axis (A D ).

[0017] Patches configured perpendicular (or almost perpendicular) to the device longitudinal axis (A D ) can help to retard the advancement of the meniscus, thereby helping to fill or shape the (liquid) meniscus. For example, such patches can in particular provide a transition interface for transitioning from a (more) attractive surface material to a (more) repulsive surface material along the device longitudinal axis (A D ). Thus, in embodiments, the liquid meniscus can slow down and / or stop at the transition interface. Moreover, the shape of such patches can in particular influence the shape of the meniscus, such as patches with a greater degree of curvature leading to a greater degree of curvature of the interface, thereby resulting in a higher jet velocity. In embodiments, a plurality of such patches can help to slow down or stop the advancement of the liquid meniscus over a certain area (rather than a single fixed transition interface). In embodiments, such patches can be chosen from rectangular (with straight edges), curved shapes (such as crescent or (semi-)circular or elliptical), stadium shapes, disc shapes and triangular (with straight and / or curved edges). In particular, more curved patches (e.g. crescent, circular, etc.) can help to eject a jet with a smaller diameter and a higher velocity. Moreover, straight edge patches (e.g. with straight edges and / or rectangular) can help to eject a jet with a larger diameter and a lower velocity. Furthermore, wavy structured patches (also) can help to eject a jet with a larger diameter and a lower velocity. Such embodiments will be further discussed below.

[0018] Patches configured parallel (or almost parallel) to the device longitudinal axis (A D) Parallel (or almost parallel) configured patches can influence the (hydro) dynamics of the liquid jet during jet formation, i.e. can in particular determine the shape and / or trajectory of the liquid jet. Such patches can in particular influence the directionality, stability and reproducibility of the liquid jet. In such embodiments, the patches can contribute to confine the jet in a more affinity rich area, in particular in case the directionality of the jet can be defined by said confinement. More specifically, by suppressing the wiggling tail of the (ejected) liquid jet, the reproducibility of the jet can be improved. In embodiments, such patches can be affinity rich and further, such patches can be (at least partially) surrounded by repelling material, such that the liquid can be confined in a more affinity rich area. I.e. in embodiments, such patch configuration can define a more affinity rich area, wherein the movement (or flow) of the liquid can be accelerated (relative to a less affinity rich area). Further, in embodiments, such (extending) patches can be configured at an angle to the device longitudinal axis (A D ) such that the ejection of the liquid jet at an angle to the device longitudinal axis is facilitated. In further embodiments, multiple such patches can be configured on the chamber wall to determine the trajectory of the (ejected) liquid jet.

[0019] Further, a combination of patches can provide a heterogeneous surface chemistry to the chamber wall, such that a stable and reproducible jet is facilitated. Embodiments comprising such configurations can have: Converging patches (comprising repelling material) with affinity areas between the patches, which can provide a gradually confined jet along the device longitudinal axis (A D ). Such a structure can have the advantage that a smooth transition to a smaller confinement area is enabled, in particular in case the patches can be curved. Further, in embodiments, triangular or trapezoidal shaped patches can (also) enable a smooth transition to a smaller confinement area; Diverging patches (comprising repelling material) with affinity areas between the patches, which can provide a more diffuse jet and a (random) wiggling tail. This can be useful for applications where a dispersed deposition of the liquid is desired; Wavy patches defined along the device longitudinal axis (A D ), which can increase the number of transitions (between repelling and affinity areas), whereby the jet can slow down and be confined in a specific area.

[0020] These aspects will be discussed in further detail below.

[0021] As mentioned above, in embodiments, the microfluidic device for jetting can comprise a main chamber defined by a chamber wall. In embodiments, the first chamber end can comprise a first chamber opening. In particular, the first chamber end can comprise a first chamber opening for jetting from the main chamber. In embodiments, a portion of the first chamber end can comprise the first chamber opening. For example, in embodiments, the first chamber end can be a closed surface and the first chamber opening can be a hole of a smaller size than the first chamber end and the liquid jet can in particular escape via the first chamber opening. However, in other embodiments, the entire first chamber end can comprise the first chamber opening, i.e. in embodiments, the cross-sectional area (and shape) of the first chamber opening can be identical to the cross-sectional area (and shape) of the first chamber end.

[0022] In embodiments, the main chamber can have an extended (elongated) shape (or geometry), i.e. one dimension of the main chamber, in particular the length of the main chamber, can be (significantly) larger than the width and height of the main chamber. In particular, in embodiments, the main chamber can have a device longitudinal axis (A D ), in particular along the length direction of the main chamber. In particular, along the device longitudinal axis (A D ), the main chamber can have a chamber length (L c ). More particularly, the chamber length (L c ) can be defined between the first chamber end and the second chamber end. The main chamber can have a plurality of different shapes and geometries, such embodiments are described herein.

[0023] In particular, the main chamber can have a prismatic or prismatic-like geometry, in particular wherein the main chamber can have a shape selected from a tetraprism, a pentaprism, a hexaprism, etc. In embodiments, the main chamber can have a shape selected from a P-edged prism, wherein the cross-section of the chamber wall in a plane perpendicular to the device longitudinal axis (A D ) is a P-edged polygon. In such embodiments, P can be at least 3, such as at least 4, in particular at least 5. Further, in embodiments, P can be at most 50, such as at most 25, in particular at most 10. In embodiments, the main chamber can also comprise a circular cross-section (see below), wherein the circular cross-section can be considered a P-edged polygon, wherein P is infinite.

[0024] In embodiments, the main chamber, such as in particular the chamber wall, can have a cross-sectional shape (in a plane perpendicular to the device longitudinal axis (A D ) comprising equal edges. However, in alternative embodiments, the main chamber (in a plane perpendicular to the device longitudinal axis (A D) perpendicular to the longitudinal axis (A D ) of the device, can have a cross-sectional shape comprising unequal sides, for example, a rectangular cross-section with different width and height. In further embodiments, a portion of the chamber wall can be curved, for example, a rectangular cross-section with two curved sides, in a cross-section perpendicular to the longitudinal axis (A c ) of the device. Such a geometry can also be referred to as a rounded rectangular geometry. Further, in embodiments, the main chamber can have a cylindrical shape, wherein, in a plane perpendicular to the axis of the cylinder, the main chamber can have a circular cross-section. Further, in embodiments, the main chamber can have a cross-sectional shape approximating a shape selected from the group comprising a stadium shape and an ellipse.

[0025] In embodiments, the chamber height (H c ) of the main chamber can be selected from the range of 1 - 1000 μm, such as from the range of 2 - 500 μm, for example from the range of 5 - 400 μm, in particular from the range of 10 - 200 μm. In embodiments, the chamber width (W c ) of the main chamber can be selected from the range of 1 * H c - 20 * H c , such as from the range of 2 * H c - 10 * H c , in particular from the range of 4 * H c - 8 * H c , more in particular from the range of 5 * H c - 7 * H c . In embodiments, the chamber length (L c ) of the main chamber can be selected from the range of 10 - 10000 μm, such as from the range of 100 - 5000 μm, in particular from the range of 500 - 1000 μm.

[0026] Thus, in specific embodiments, the main chamber has a chamber height (H c ) selected from the range of 5 - 400 μm, a chamber width (W c ) selected from the range of 2 * H c - 10 * H c , and a chamber length (L c ) selected from the range of 100 - 5000 μm, wherein along at least 80% of the chamber length (L c ) the main chamber has a cross-sectional shape approximating a shape selected from the group consisting of a rounded rectangular, a stadium shape, and an ellipse.

[0027] As mentioned above, the main chamber can be configured to contain a liquid. In embodiments, the liquid can be water. However, in embodiments, the liquid can also be different from water, such as a liquid selected from glycerol, an alcohol, an organic solvent, and (other) hydrocarbons. For example, in embodiments, the liquid can comprise an oil. Further, in embodiments, the liquid can comprise a dissolved medicament, such as a vaccine or insulin. In particular, the liquid can comprise additives, such as thickening agents, emulsifiers, surfactants, viscoelastic additives, pigments, and biomolecules. Further, in embodiments, the liquid can comprise a saline solution. In further embodiments, the liquid can comprise a polypeptide, such as a protein or a cyclic peptide (e.g. cyclosporine). Further, in embodiments, the liquid can comprise a skin penetration enhancer, such as an enhancer selected from alcohols (e.g. ethanol), sulfoxides, surfactants (e.g. sodium dodecyl sulfate), limonene, propylene glycol, and azone.

[0028] In embodiments, the liquid contained in the main chamber can fill a portion of the main chamber, the remainder of which can be a gas (e.g. air). The liquid can in particular have a liquid meniscus, i.e. the liquid surface in contact with the gas and the chamber wall can be curved. The curvature of the meniscus can be a result of the competition between adhesive and cohesive energies between the molecules of the liquid and the chamber wall. In particular, heterogeneous surface chemical properties (e.g. differences in affinity of different portions (or regions) of the chamber wall) can contribute to the ejection of the liquid from the main chamber.

[0029] The affinity of a surface can be defined as the ability of a liquid to spread on the surface, wherein the affinity is quantitatively defined by the (equilibrium) contact angle Q of the liquid. The (equilibrium) contact angle Q can be defined as the angle at which the liquid-gas interface intersects the solid-liquid interface, i.e. the angle at which the liquid meniscus meets the chamber wall. The contact angle as described herein can in particular refer to the contact angle of the liquid with the (first / second) surface material at room temperature (20 °C), 1 atm atmospheric pressure, and air as the gas. An equilibrium contact angle Q < 90° indicates that the surface is affinitive to the liquid, which can spread over a larger area of the surface. An equilibrium contact angle Q > 90° indicates that the surface is repulsive to the liquid, which can minimize the contact area with the surface. In embodiments, the equilibrium contact angle Q of a repulsive surface can be > 91°, such as Q > 93°, in particular Q > 95° (for the liquid). In embodiments, the equilibrium contact angle Q of a repulsive surface can be (further) > 91°, such as Q > 93°, in particular Q > 95° (for the liquid). Additionally or alternatively, in embodiments, the equilibrium contact angle Q of an affinitive surface can be < 89°, such as Q < 87°, in particular Q < 85° (for the liquid). Further, in embodiments, the equilibrium contact angle Q of an affinitive surface can be < 89°, such as Q < 87°, in particular Q < 85° (for the liquid). It will be clear to the skilled person that the equilibrium contact angle Q depends on the combination of surface material and liquid. In particular, the equilibrium contact angle of a material can differ for liquids, in particular the contact line (meniscus) behavior of a liquid can differ. It is (further) noted that the presence of impurities in the liquid can affect the equilibrium contact angle Q.

[0030] In embodiments, the chamber wall can comprise a (surface) pattern of a first surface material and a second surface material, wherein the first surface material can have an equilibrium contact angle Q1 (for the liquid) and the second surface material can have an equilibrium contact angle Q2 (for the liquid). In particular, the first surface material can be repulsive (for the liquid), wherein Q1 > 90°. In some embodiments, the second surface material can be affinitive (for the liquid). However, in other embodiments, the second surface material can also be repulsive (for the liquid). In embodiments, the first surface material can (always) have a larger equilibrium contact angle (for the liquid) than the second surface material. In particular, Q1 - Q2 > 20°, such as Q1 - Q2 > 30°, in particular Q1 - Q2 > 40°.

[0031] In embodiments, at least 1 % of the chamber wall (in particular the pattern) comprises the first surface material, such as at least 2%, in particular at least 5%. In further embodiments, at least 10% of the chamber wall (in particular the pattern) comprises the first surface material, such as at least 20%, in particular at least 30%. In further embodiments, at least 50% of the chamber wall (in particular the pattern) comprises the first surface material, such as at least 60%, in particular at least 70%. The term "first surface material" can also refer to a plurality (different) first surface materials, such as different repelling materials (see also below). For example, in embodiments where a plurality of patches comprises the first surface material, different patches can comprise different first surface materials.

[0032] In further embodiments, at least 1 % of the chamber wall (in particular the pattern) comprises the second surface material, such as at least 2%, in particular at least 5%. In further embodiments, at least 10% of the chamber wall (in particular the pattern) comprises the second surface material, such as at least 20%, in particular at least 30%. In further embodiments, at least 50% of the chamber wall (in particular the pattern) comprises the second surface material, such as at least 60%, in particular at least 70%. The term "second surface material" can also refer to a plurality (different) second surface materials, such as different hydrophilic materials (see also below). For example, in embodiments where a plurality of patches comprises the second surface material, different patches can comprise different second surface materials.

[0033] In further embodiments, the pattern can cover at least 90% of the chamber wall (surface area), such as at least 95%, including 100%. Thus, in embodiments, the first surface material and the second surface material can (together) cover at least 90% of the chamber wall (surface area), such as at least 95%, including 100%.

[0034] As mentioned above, the affinity (or "affinity degree") of the first (or second) surface material can depend on the liquid contained in the main chamber. In embodiments, the affinity of the liquid to the first (or second) surface material can depend on the adhesion and cohesion between the liquid molecules and the first (or second) surface material.

[0035] For example, in embodiments, the liquid can comprise water. In such embodiments, the first surface material and / or the second surface material can comprise a repellent material, in particular at least the first surface material can comprise a repellent material. In further embodiments, the repellent material can be selected from the group consisting of polydimethylsiloxane (PDMS), polyvinyl chloride (PVC) and polytetrafluoroethylene (PTFE). In further embodiments, the repellent material can comprise a repellent coating. For example, the repellent material can comprise a thiol-coated gold. Further, in embodiments, the repellent material can further comprise graphene oxide, in particular a graphene oxide coating. In particular, the repellent material can comprise a repellent film, wherein the repellent film can be obtained by depositing graphene oxide on the surface of the film (by chemical vapor deposition). Such a film can in particular be referred to as a highly transparent, flexible and super-repellent film (HTFS).

[0036] In further embodiments, the second surface material can comprise a hydrophilic material. In particular, the hydrophilic material can be a metal oxide, such as a metal oxide selected from the group consisting of AI2O3, TiO2and SiO2. In further embodiments, the hydrophilic material can comprise one or more of gold, platinum, chromium and titanium.

[0037] In further embodiments, the first surface material and / or the second surface material can comprise a lipophobic material, in particular at least the first surface material can comprise a lipophobic material, or in particular at least the second surface material can comprise a lipophobic material. In particular, the lipophobic material can be selected from the group consisting of a fluorosurfactant, a cyclic olefin copolymer (COC) and a cyclic olefin polymer (COP). Further, in embodiments, the lipophobic material can comprise a chitosan coating.

[0038] In further embodiments, the second surface material can comprise a lipophilic material. In particular, the lipophilic material can be selected from the group consisting of parylene, alkylsilane (e.g. octadecylsilane), polyethylene (e.g. PTFE) and polypropylene. Further, in some embodiments, the lipophilic material can comprise a thiol coating (e.g. dodecanethiol) or a carbon-based coating.

[0039] In embodiments, the (surface) pattern can comprise (surface) patches. In embodiments, a surface patch can be a two-dimensional shape defined on the (inner) surface of the chamber wall. In embodiments, a patch can comprise one of the first surface material and the second surface material.

[0040] In embodiments, the patch can be a two-dimensional area defined by a contour. In particular, the contour can be a single smooth contour, such as an ellipse. Alternatively, in embodiments, the patch can have a contour defined by a plurality of line segments, such as a rectangle. In further embodiments, at most two line segments can be curved, such as a half-stadium. Thus, in embodiments, the shape of the patch can approximate a shape (or geometry) selected from the group consisting of a triangle, trapezoid, rectangle, crescent, ellipse, circle, wave, stadium, and half-stadium.

[0041] In embodiments, the patch can in particular have a patch boundary. In embodiments, the patch can be defined on the chamber wall surface (anywhere). In particular, the patch can be defined near the first chamber end, in particular near the first chamber opening. Thus, in embodiments, at least 50% of the patch boundary can be in contact with the other of the first surface material and the second surface material. In particular, in such embodiments, the remaining part of the patch boundary can in particular be arranged at the first chamber end, i.e. in embodiments, the patch boundary can define at least a portion of the first chamber end. In further embodiments, at least 60% of the patch boundary can be in contact with the other of the first surface material and the second surface material. In still further embodiments, at least 70% of the patch boundary can be in contact with the other of the first surface material and the second surface material. Furthermore, in embodiments, the patch can comprise the first surface material, and at least 80% of the patch boundary can be in contact with the second surface material. Similarly, in embodiments, the patch can comprise the second surface material, and at least 80% of the patch boundary can be in contact with the first surface material. In still further embodiments, the patch can be in contact with the other of the first surface material and the second surface material along more than 99% (including 100%) of the patch boundary.

[0042] In particular embodiments, the patch boundary can comprise a plurality of boundary portions. For example, a (annular) patch arranged on the chamber wall can have a patch boundary comprising two boundary portions. In particular, at least 50% of the patch boundary comprising one or more boundary portions can be in contact with the other of the first surface material and the second surface material.

[0043] Alternatively, in embodiments, the patch can be defined away from the first chamber end and the second chamber end. In such embodiments, the patch can comprise one of the first surface material and the second surface material, and the entire patch boundary can be in contact with the other of the first surface material and the second surface material. For example, in embodiments, the patch comprises the first surface material, and the (entire) patch boundary can be in contact with the second surface material. In other embodiments, the patch comprises the second surface material, and the (entire) patch boundary can be in contact with the first surface material.

[0044] In embodiments, the chamber wall may have a (wall) surface area (S w In an embodiment, the patch may have a (patch) surface area (S P In particular, the surface area of ​​the patch (S P ) and the surface area of ​​the chamber wall (S w ) can be defined as 10 —5 ≤S P / S w ≤2*10 —1 , such as 10 —4 ≤S P / S w ≤2*10 —1 , especially 10 —3 ≤S P / S w ≤2*10 —1 In an embodiment, 10 —2 ≤S P / S w ≤2*10 —1 In addition, in an embodiment, 10 —5 ≤S P / S w ≤10 —1 , such as 10 —5 ≤S P / S w ≤10 —2 , such as 10 —5 ≤S P / S w ≤10 —3 , especially 10 —5 ≤S P / S w ≤10 —4 In a further embodiment, the surface area of ​​the sheet (S P ) and the surface area of ​​the chamber wall (S w ) can be defined as S P / S w At least 10 —5 , such as at least 10 —4 , in particular at least 10 —3 In a further embodiment, the surface area of ​​the sheet (S P ) and the surface area of ​​the chamber wall (S w ) can be defined as S P / S w Maximum is 2*10 —1 , such as a maximum of 2*10 —2 , especially the maximum is 2*10 —3 In an embodiment, the surface area of ​​the sheet region (SP ) can be at least 1 pm 2 , such as at least 10 pm 2 , in particular at least 100 pm 2 . In further embodiments, the surface area (S P ) of the patch can be at least 0.01 mm 2 , such as at least 0.1 mm 2 , in particular at least 1 mm 2 .

[0045] The pattern can in particular comprise a plurality of patches, wherein each patch comprises the first surface material, or wherein each patch comprises the second surface material. In such embodiments, each patch (of the plurality of patches) can have an independently selected surface area (S P ) of the patch, such as an independently selected surface area (S P ) of the patch satisfying 10 —5 ≤ S P / S w ≤ 2*10 —1 , such as 10 —4 ≤ S P / S w ≤ 2*10 —1 , in particular 10 —3 ≤ S P / S w ≤ 2*10 —1 (see also above).

[0046] Further, in embodiments, the pattern can have a (pattern) surface area S PP , in particular of the first surface material, or in particular of the second surface material. In particular, the ratio of the surface area (S PP ) of the pattern to the surface area (S w ) of the chamber wall can be defined as 0.01 ≤ S PP / S w ≤ 0.95, such as 0.1 ≤ S PP / S w ≤ 0.95, in particular 0.5 ≤ S PP / S w ≤ 0.95. Further, in embodiments, 0.05 ≤ S PP / S w ≤ 0.9, such as 0.05 ≤ S PP / S w ≤ 0.7, in particular 0.05 ≤ S PP / S w ≤ 0.5, more in particular 0.05 ≤ S PP / S w≤0.3.

[0047] In embodiments, the pattern surface area (S PP ) can be at least 0.001 mm 2 , such as at least 0.01 mm 2 , in particular at least 0.1 mm 2 , more in particular 1 mm 2 . In further embodiments, the pattern surface area (S PP ) can (even) be at least 5 mm 2 , such as at least 10 mm 2 .

[0048] In particular, the (pattern) surface area S PP may refer to the total surface area of the plurality of patches of a material, such as to the total surface area of the plurality of patches comprising the first surface material, or such as to the total surface area of the plurality of patches comprising the second surface material. Hence, in embodiments, the plurality of patches can have a total (pattern) surface area S PP .

[0049] Further, as mentioned above, in embodiments, the chamber wall is not necessarily flat. In some embodiments, one or more surfaces of the chamber wall can in particular have a curvature. In such embodiments, the patches can (still) be configured (or defined) along the curved chamber wall. In particular, in such embodiments, the patches can (also) be curved, such as having the same curvature as the chamber wall.

[0050] As mentioned above, the patches can (substantially) be two-dimensional shapes. Hence, in embodiments, the patches can have a patch length L P and a patch width W P . In embodiments, the patches can in particular extend. In particular, a patch longitudinal axis (A P ) can be defined along the extension direction. In embodiments, the patches can have a patch length (L P ) along the patch longitudinal axis (A P ), and the patches can have a patch width (W P ) perpendicular to the patch longitudinal axis (A P ). In embodiments, the patch length (L P ) of the patches can be larger than the patch width (W P ) such that L P ≥ 1.25*W P , such as L P ≥ 1.5*W P , in particular L P ≥ 2*W P , more in particular L P ≥ 5*WP More particularly L P ≥ 10*W P In a specific embodiment, the patch has a patch longitudinal axis (A P ), wherein the patch has a patch length L P along the patch longitudinal axis (A P ) and a patch width W P perpendicular to the patch longitudinal axis (A P ) (wherein the patch length (L P ) and the patch width (W P ) are measured along the chamber wall), wherein L P ≥ 1.5*W P .

[0051] The elongated shape is particularly helpful in controlling the propulsion of the liquid meniscus. For example, an elongated patch comprising an affinity second surface material and oriented along the device longitudinal axis (A D ) can particularly (locally) accelerate the flow of liquid (towards the first chamber opening). Similarly, in embodiments, an elongated patch comprising a first surface material and oriented perpendicular to the device longitudinal axis (A D ) can retard the propulsion of the liquid meniscus. Thus, in this way, the propagation of the liquid jet can be controlled by the structure of the patch (i.e. the shape and orientation of the patch (surface)).

[0052] In embodiments, the patch can be a continuous surface, i.e. the entire surface area of the patch can be composed of the first surface material or the second surface material. However, in other embodiments, the patch can not be a continuous surface, particularly, the patch can comprise (affinity or repelling) dots. In embodiments, each patch comprises (affinity or repelling) dots can have a total surface area (S D ). In embodiments, S D / S P ≥ 0.3, such as S D / S P ≥ 0.5, particularly S D / S P ≥ 0.7. Particularly, 0.8 ≤ S D / S P < 1.0, such as 0.85 ≤ S D / S P < 1.0, particularly 0.9 ≤ S D / S P < 1.0, more particularly 0.95 ≤ S D / S P<1.0. In embodiments, the dots may be circular dots comprising the first surface material or the second surface material. However, in other embodiments, the dots may not (necessarily) be circular. In particular, the dot shape may be selected from an oval, an ellipse, a square, a hemispherical stadium, and a parallelogram. Furthermore, in embodiments, the dots contained in each patch may exhibit polydispersity in size and shape, i.e., the dots may have unique (and different) sizes and shapes. Thus, in this way, the patch surface may be specifically covered with dots comprising the first surface material or the second surface material.

[0053] In an embodiment, the patch width W P Available from 0.01*L c —0.2*L c Select from the range, such as 0.05*L c —0.2*L c , especially 0.1*L c —0.2*L c In addition, in an embodiment, the slice width W P Available from 0.01*L c —0.1*L c Select within the range, such as 0.01*L c —0.05*L c In an embodiment, the vertical axis of the slice (A P ) can be aligned with the longitudinal axis of the device (A D ) forms an angle α≥80°, such as α≥85°. In particular, the longitudinal axis of the slice (A P ) can (even) be aligned with the longitudinal axis of the device (A D ) is perpendicular, i.e. α=90°. Furthermore, in this embodiment, the sheet area may in particular comprise a first surface material. Thus, in a specific embodiment, the sheet area comprises a first surface material, wherein the longitudinal axis (A) of the sheet area P ) and the longitudinal axis of the device (A D ) forms an angle α≥80°, and wherein the slice width W P From 0.01*L c —0.2*L c Such a region may provide the advantage of first blocking the advancement of the meniscus. For example, this may be achieved by strategically placing the region along (and perpendicular to) the longitudinal axis (A) of the device. D ) An elongated section is provided at a predetermined distance from the end of the second chamber to specifically fill the main chamber to a desired volume.

[0054] In an embodiment, the sheet area may be configured to be spaced from 0.3*L to the end of the second chamber. c —0.9*L c Select the (shortest) distance within the range, such as 0.4*Lc — 0.8 * L c — 0.5 * L c — 0.7 * L c — 0.3 * L D — 0.9 * L D — 0.5 * L c — 0.9 * L c — 0.5 * L

[0055] In the context of a slice, the term "almost parallel" can mean that the slice longitudinal axis (A P ) forms an angle a with the device longitudinal axis (A D ), wherein a < 30°, such as a < 20°, in particular a < 10°.

[0056] In the context of a slice, the term "almost perpendicular" can mean that the slice longitudinal axis (A P ) forms an angle a with the device longitudinal axis (A D ), wherein a > 60°, such as a > 70°, in particular a > 80°.

[0057] It is noted that the measurement of the angle a can be made in a counter-clockwise (or clockwise) direction from the device longitudinal axis (A D ) to the slice longitudinal axis (A P ). Thus, the angle a can in particular be the smallest angle between the device longitudinal axis (A D ) and the slice longitudinal axis (A P ), i.e. there is no difference between -a and +a, both of which can be considered as a.

[0058] In embodiments, the slice length (L P ) can be selected from the range of 0.2 * L c — 0.95 * L c , such as from the range of 0.3 * L c — 0.85 * L c , in particular from the range of 0.4 * L c — 0.75 * L c , more in particular from the range of 0.5 * L c — 0.65 * L c . In embodiments, the slice longitudinal axis (AP ) can be angled with the device longitudinal axis (A D ) by an angle a < 30°, such as a < 20°, in particular a < 10°. In particular, the patch longitudinal axis (A P ) can be (even) parallel to the device longitudinal axis (A D ), i.e. a = 0°. Further, in such embodiments, the patch can in particular comprise the second surface material. Thus, in specific embodiments, the patch comprises the second surface material, wherein the patch longitudinal axis (A P ) forms an angle a < 30° with the device longitudinal axis (A D ), and wherein the patch length (L P ) is selected from the range of 0.2 * L c - 0.95 * L c . Such a patch can accelerate the liquid flow towards the first chamber opening. In particular, such a patch can direct the liquid meniscus in the direction of the patch longitudinal axis (A P ). More particularly, such a patch can be long enough so that it extends from the end of the first chamber to a point close to the liquid meniscus. Thus, in this way, the liquid jet can be directed along the chamber wall to the first chamber opening, thereby resulting in a higher stability and reproducibility of the ejected microfluidic jet.

[0059] In embodiments, the configuration of the patches can influence the trajectory of the liquid jet and / or the volume of the liquid fillable main chamber. In particular, a patch can be defined on a surface of the main chamber. Thus, in some cases, a portion of the chamber wall can comprise a patch, whereas the portion of the chamber wall opposite to the patch can (not necessarily) comprise another patch. This can result in only a portion of the meniscus being pinched (i.e. the liquid meniscus is pinched on only one side of the chamber wall) and / or the trajectory of the liquid jet being twisted disproportionately (i.e. the liquid jet can be accelerated disproportionately on one side of the chamber wall). This can be alleviated by arranging one or more patches symmetrically on the chamber wall. Thus, in embodiments, the pattern can comprise one or more patches, in particular wherein the patches can be configured on the chamber wall so that the one or more patches are arranged symmetrically on the chamber wall.

[0060] In some embodiments, during operation of the microfluidic device, the liquid jet can be ejected at an angle from the first chamber opening. In embodiments, this can be controlled (or alleviated) by configuring (only) one patch, wherein the patch can be configured to (at least partially) determine the trajectory of the ejected liquid jet. Thus, in this way, even a single patch can contribute to an improved stability and reproducibility of the liquid jet. Further, in embodiments, a pattern comprising (even) one (single) patch can have a plane of symmetry, e.g. the plane of symmetry can pass through the device's elongation axis and the centroid of the patch can lie within the plane of symmetry.

[0061] Thus, in embodiments, one or more panels may be configured such that the panel has a plane of symmetry, and in particular, the plane of symmetry may pass through and be parallel to the longitudinal axis of the device (A). D Additionally or alternatively, in an embodiment, the patch may (also) be configured such that the patch has a plane of symmetry, in particular, the plane of symmetry may be perpendicular to the longitudinal axis of the device (A D Thus, in a specific embodiment, the pattern (of the first surface material and the second surface material) has a plane of symmetry (wherein the longitudinal axis of the device (A) D ) coincides with the plane of symmetry, or where the longitudinal axis of the device (A D ) is perpendicular to the plane of symmetry).

[0062] In an embodiment, the longitudinal axis (A D ) in a plane perpendicular to the chamber wall (consisting of the main chamber) may have a (chamber) perimeter length P c In embodiments where the main chamber has a cylindrical geometry, the periphery of the device is perpendicular to the longitudinal axis (A D ), the chamber wall perimeter may have a chamber (boundary) length P c .

[0063] As mentioned above, in embodiments, the patch may be defined on the chamber wall in any direction, i.e., the patch longitudinal axis (A P ) can be aligned with the longitudinal axis of the device (A D ) is at an angle α. Therefore, at a position perpendicular to the longitudinal axis of the device (A D ), a portion of the chamber wall can in particular be covered by the patch. In particular, the patch can be along a cross section having a (chamber) perimeter length (P c ) of the chamber wall covering (slice area) circumference length (P p In an embodiment, the patch area may be aligned with the longitudinal axis (A D ) is vertically configured, and the (area) perimeter length (P p ) can be equal to the longitudinal axis of the device (A D ) The length of the slice on the vertical cross section (L P ). In addition, in embodiments, the patch area may be configured to be aligned with the longitudinal axis (A) of the device. D ) and parallel to the longitudinal axis of the device (A D ) on the vertical cross section, the perimeter length of the patch (P p ) can be equal to the width of the area (W P In other embodiments, the vertical axis of the slice (A P ) can be configured to align with the longitudinal axis of the device (A D ) and is at an angle α to the longitudinal axis of the device (A D ) on the vertical cross section, the perimeter length of the patch (Pp ) can be found in W P —L P within the range.

[0064] In an embodiment, the longitudinal axis (A D ) in a cross section perpendicular to the axis of the slice, the slice may cover a portion of the chamber wall. In particular, the longitudinal axis of the slice (A P ) can be configured to align with the longitudinal axis of the device (A D ) are parallel or almost parallel. Therefore, in an embodiment, the perimeter length of the patch area (P p ) can be from 0.01*P c —0.5*P c Select within the range, such as 0.05*P c —0.25*P c , especially 0.1*P c —0.2*P c Therefore, in a specific embodiment, the longitudinal axis (A D ) in a vertical cross section, the main chamber has a perimeter length (P c ) of a perimeter (or "circumference"), wherein the patch covers the perimeter length (P) along the perimeter p ), where P p From 0.05*P c —0.25*P c Select within the range.

[0065] The area coverage is 0.01*P c —0.5*P c Select within the range, such as 0.05*P c —0.25*P c The perimeter length (P) of the selected area is p ), which can provide control over the thickness (and / or volume) of the microfluidic jet. In addition, since the patch area can (only) cover the (chamber) perimeter length P c Therefore, the acceleration effect of the (microfluidic) jet on the chamber wall side covered by the patch area and the chamber wall side not covered by the patch area will be different, which helps to control the trajectory of the microfluidic jet, for example, helps to control the direction (for example, angle) of the microfluidic jet ejected from the first chamber opening. In addition, the patch area coverage is 0.01*P c —0.5*P c Select within the range, such as 0.05*P c —0.25*P c The perimeter length (P) of the selected area is p ), which can provide control over the shape (and position) of the meniscus. That is, a portion of the chamber wall can include a patch (whose perimeter length (Pp ) can be selected in the range of 0.01 * P c — 0.5 * P c ) can not (have to) comprise the patch. This can result in only a part of the meniscus being pinched (i.e. the liquid meniscus is pinched on one side of the chamber wall only), and thus, the meniscus can have an (un) symmetric shape determined by the (patch) perimeter length (P D ) can be selected in the range of 0.01 * P c — 0.99 * P c ) can not (have to) comprise the patch. This can result in only a part of the meniscus being pinched (i.e. the liquid meniscus is pinched on one side of the chamber wall only), and thus, the meniscus can have an (un) symmetric shape determined by the (patch) perimeter length (P p ) can be selected in the range of 0.01 * P

[0066] In particular, the patch longitudinal axis (A P ) can be configured perpendicular or almost perpendicular to the device longitudinal axis (A D ). In embodiments, the (patch) perimeter length (P p ) can be selected in the range of 0.2 * P c — P c , such as in the range of 0.4 * P c — P c , in particular in the range of 0.6 * P c — P c . Thus, in specific embodiments, in a cross-section perpendicular to the device longitudinal axis (A D ), the main chamber has a perimeter (or "circumference") of (chamber) perimeter length (P c ), wherein the patch covers along this perimeter a (patch) perimeter length (P p ), wherein P p is selected in the range of 0.4 * P c — P c .

[0067] In the application of the microfluidic device it can be necessary to control the liquid, e.g. it can be necessary to fill the liquid to a predetermined volume of the main chamber. Further, in the application of the microfluidic device energy can be provided to the liquid such that a microfluidic jet is ejected from the microfluidic device via the first chamber opening. Thus, by this configuration of the patch (on the chamber wall), in embodiments, the chamber wall can have a heterogeneous surface chemistry (i.e. a difference in affinity). In particular, this heterogeneous surface chemistry can help to eject a stable and reproducible microfluidic jet.

[0068] As mentioned above, in embodiments, the pattern can comprise a plurality of patches. In embodiments, the pattern can comprise a first group of n patches. In embodiments, each patch of the first group can comprise a first surface material. In other embodiments, each patch of the first group can comprise a second surface material.

[0069] In embodiments, n can be at least 2, such as at least 5, in particular at least 10. In embodiments, the n patches can be arranged consecutively (downstream of the end of the second chamber along a direction parallel to the longitudinal axis (A D ) of the device). Here, two patches of the consecutive arrangement can refer to the arrangement of a second patch downstream of a first patch. Also, in embodiments, the n patches can also be arranged consecutively, i.e. each patch of the first group can be arranged downstream of a preceding patch of the first group (except for the first patch arranged closest to the end of the second chamber). In embodiments, the distance between any two consecutive patches of the first group can be the same, i.e. the patches of the first group can be equally spaced. However, in other embodiments, the distance between any two consecutive patches of the first group can also be different. In embodiments, the patches of the first group can be arranged perpendicular or almost perpendicular to the longitudinal axis (A D ) of the device. In particular, the patch longitudinal axis (A P ) of each patch of the first group can form an angle a > 80°, such as a > 85°, in particular a = 90°, with the longitudinal axis (A D ) of the device.

[0070] It is noted that the terms "upstream" and "downstream", such as in the context of the liquid jet, can in particular relate to the arrangement of an item or feature with respect to the longitudinal axis (A D ) of the device, wherein a second position along the longitudinal axis (A D ) of the device (closer to the end of the second chamber than the first position) is "upstream" with respect to a first position along the longitudinal axis (A D ) of the device, and a third position along the longitudinal axis (A D ) of the device (further away from the end of the second chamber than the first position) is "downstream".

[0071] Thus, in a specific embodiment, the pattern comprises a first group of n patches, wherein n > 2, wherein the n patches are arranged consecutively (and equally spaced) downstream of the end of the second chamber (along a direction parallel to the longitudinal axis (A D ) of the device), wherein each patch of the first group comprises a first surface material, wherein the patch longitudinal axis (A P ) of each patch of the first group forms an angle a > 80° with the longitudinal axis (A D ) of the device.

[0072] During application of the microfluidic device, energy can be provided to the liquid, thereby ejecting a microfluidic jet. When the liquid meniscus is propelled in the direction of the device longitudinal axis (A D ) the one or more segments of the first group can comprise a first surface material, and thus can hinder the propulsion of the liquid meniscus. In particular, this arrangement of segments of the first group can stepwise reduce the ejection velocity of the microfluidic jet. Thus, the velocity of the microfluidic jet can be controlled in particular by the number of segments, the orientation angle of the segments, the equilibrium contact angle of each segment, and the distance between adjacent segments.

[0073] In embodiments, the pattern can comprise a second group of k segments. In embodiments, each segment of the second group can comprise a second surface material.

[0074] In embodiments, k can be at least 2, such as at least 5, in particular at least 10. In embodiments, each segment of the second group can be configured at a (shortest) distance from the second chamber end (measured in the direction of the device longitudinal axis (A D ) selected from the range of 0.3*L c — 0.9*L c , such as from 0.3*L c — 0.75*L c , such as from 0.3*L c — 0.6*L c . Further, in embodiments, each segment of the second group can be configured at a (shortest) distance from the second chamber end (measured in the direction of the device longitudinal axis (A D ) selected from the range of 0.4*L c — 0.9*L c , such as from 0.5*L c — 0.9*L c , such as from 0.6*L c — 0.9*L c . In embodiments, the (shortest) distance of each of the k segments of the second group from the second chamber end can be the same. Alternatively, the (shortest) distance of each of the k segments of the second group from the second chamber end can be individually selected (such as from the range of 0.3*L c — 0.9*L c , see above).

[0075] In embodiments, the segments of the second group can be configured parallel or almost parallel to the device longitudinal axis (A D ). In particular, the segment longitudinal axis (A P ) of each segment of the second group can be parallel or almost parallel to the device longitudinal axis (A D) forms an angle a < 30°, such as a < 20°, in particular a < 10°, more in particular a = 0°. Further, in embodiments, the second set of segments can converge or diverge towards the first chamber end.

[0076] Thus, in embodiments, the pattern comprises a second set of k segments, wherein k > 2, wherein each segment of the second set comprises a second surface material, wherein each segment of the second set is configured at a (shortest) distance from the second chamber end (measured along the device longitudinal axis (A D ) is chosen from the range of 0.3 * L c - 0.9 * L c , wherein the segment longitudinal axis (A P ) of each segment of the second set forms an angle a < 30° with the device longitudinal axis (A D ).

[0077] As mentioned above, in embodiments, the segments can be two-dimensional shapes. Thus, the shortest distance can be measured from a point on the segment profile closest to the second chamber end to the second chamber end.

[0078] In applications of the microfluidic device, energy can be provided to the liquid, resulting in ejection of a microfluidic jet. In embodiments, the second set of segments can comprise a second surface material. In particular, the second surface material can be hydrophilic, and thus, the second set of segments can be configured to accelerate and direct the liquid jet upon ejection from the microfluidic device. Thus, as mentioned above, in embodiments, the second set of segments can be configured closer to the first chamber end than to the second chamber end (shortest distance). Further, in embodiments, the hydrophilicity of the second surface material can provide the advantage of (relatively) accelerating the liquid flow along the segments. Further, the second set of segments can be (i) configured parallel or almost parallel to the device longitudinal axis (A D ) and (ii) converging or diverging towards the first chamber end, thereby directing the jet to flow along a predetermined trajectory, such that a stable and reproducible jet can be ejected. Thus, the velocity of the microfluidic jet can be controlled in particular by the number of segments, the shape of the segments, the orientation angle of the segments, the contact angle of each segment, and the distance between adjacent segments.

[0079] In embodiments, the pattern can comprise a third set of m segments. In embodiments, m can be at least 2, such as at least 5, in particular at least 10. In embodiments, each segment of the third set can comprise a second surface material.

[0080] In embodiments, the center of mass of the third set of segments can be disposed along an axis (A M ) defined by the chamber wall. In particular, the axis (A M ) can be parallel to the device longitudinal axis (AD ) parallel. In embodiments, the patch longitudinal axis (A P ) of each third group of patches can form an angle a with the device longitudinal axis (A D ) (axis (A M )). In embodiments, the (all) third group of patches can form the same angle a with the device longitudinal axis (A D ). However, in other embodiments, each third group of patches can (also) form a different angle a with the device longitudinal axis (A D ). In embodiments, the patch longitudinal axis (A P ) of the third group of m patches can form an angle a with the device longitudinal axis (A D ), 5° < a < 50°, such as 5° < a < 40°, in particular 5° < a < 30°. Further, in embodiments, the patch longitudinal axis (A P ) of the third group of m patches can form an angle a with the device longitudinal axis (A D ), 10° < a < 30°, such as 15° < a < 30°, in particular 20° < a < 30°, more in particular 25° < a < 30°.

[0081] Further, in embodiments, the third group of patches can be configured consecutively along axis (A M ). In embodiments, the distance between any two consecutive patches of the third group can be the same, i.e. the patches of the third group can be configured equidistantly. In other embodiments, the distance between two consecutive patches can be different. In particular, the centroid of two consecutive patches of the third group can be configured at a first distance d1. In embodiments, d1 can be chosen from the range of 0.05 * L c - 0.5 * L c , such as from the range of 0.1 * L c - 0.4 * L c , in particular from the range of 0.2 * L c - 0.3 * L c . Note that in the present context the term "consecutive" is used interchangeably with the term "adjacent".

[0082] In embodiments, the pattern can comprise a plurality of such third groups. Thus, in specific embodiments, the pattern comprises a plurality of third groups, wherein each third group comprises a group of m patches, wherein m > 2, wherein each patch of the third group comprises a second surface material, wherein the centroid of (all) patches is along an axis (A M ) defined on the chamber wall, wherein axis (A M ) is parallel to the device longitudinal axis (A D ), wherein the patch longitudinal axis (A P ) of the m patches of the third group forms an angle a with the device longitudinal axis (AD ) forms an angle a, 5° < a < 50°, wherein the centroid of (each) two consecutive patches of the third group is arranged at a first distance d1, wherein d1 is selected from the range of 0.05*L c — 0.5*L c .

[0083] In embodiments comprising a plurality of third groups, the centroid of all patches of each third group can be distributed along a unique axis (A M ), i.e. each third group can have a respective axis (A M ). In particular, the axis (A M ) can be defined on the chamber wall, such that the distance between two consecutive axes (A M ) can be d2 (measured along a direction perpendicular to the axis (A M ) and along the chamber wall). In particular, d2 can be selected from the range of 0.2*P c — 0.5*P c , such as from the range of 0.25*P c — 0.45*P c , in particular from the range of 0.3*P c — 0.4*P c .

[0084] Thus, in particular embodiments, the axes (A M ) of two adjacent third groups are arranged with a spacing d2, wherein d2 (measured along a direction perpendicular to the axis (A M ) and along the chamber wall) is selected from the range of 0.2*P c — 0.5*P c .

[0085] Such an arrangement of patches, such as a plurality of third group patches, can help to direct and control the microfluidic jet towards the first chamber opening. Such control of the microfluidic jet helps to provide a stable and reproducible jet.

[0086] In another aspect, the present application can provide a fluid ejection system comprising a microfluidic device of the present application, a liquid supply device and a heating system. In particular, the main chamber can comprise a main chamber opening. In embodiments, the liquid supply device can be configured to supply liquid to the main chamber via the main chamber opening. In embodiments, the heating system can be configured to provide radiation to one or more chamber walls and / or the liquid in the main chamber. In specific embodiments, the present application provides a fluid ejection system comprising: (i) a microfluidic device, (ii) a liquid supply device and (iii) a (laser-based) heating system, wherein the main chamber comprises a main chamber opening, wherein the liquid supply device is configured to supply liquid to the main chamber via the main chamber opening, wherein the (laser-based) heating system is configured to provide (laser) radiation to one or more chamber walls and the liquid in the main chamber, in particular wherein the laser radiation comprises infrared laser pulses.

[0087] The fluid ejection system in particular facilitates ejection of a microfluidic jet via the first chamber opening. In embodiments, the ejection system performs some functions of: first, filling the main chamber with liquid to a predetermined volume; second, providing energy to eject a microfluidic jet via the first chamber opening.

[0088] In embodiments, the microfluidic device can comprise a pattern of one or more patches, in particular a plurality of patches each comprising a first surface material. Such a configuration can conveniently fill the main chamber with liquid to a predetermined volume. In particular, such a configuration can facilitate formation of a meniscus at a predetermined location (along the longitudinal axis (A D ) of the device.

[0089] Further, in embodiments, the main chamber can comprise a main chamber opening. In particular, the main chamber opening can be located at a distance L o from the second chamber end. In embodiments, L o may be selected from the range of 10 - 2000 μm, such as from the range of 100 - 1500 μm, in particular from the range of 500 - 1000 μm. Further, in embodiments, the main chamber opening can have a diameter D o . In particular, D o may be selected from the range of 1 - 1000 μm, such as from the range of 10 - 500 μm, in particular from the range of 25 - 300 μm, such as from the range of 25 - 200 μm. In embodiments, L o may be defined as 0 < L o / L c < 0.6, such as 0.1 < L o / L c < 0.5, in particular 0.2 < L o / L c ≤ 0.4. Note that in some embodiments, the main chamber opening can also be configured at the second chamber end, i.e. L o = 0.

[0090] In embodiments, the main chamber can be fluidically coupled to a liquid supply, i.e. liquid can flow from the liquid supply to the main chamber. Thus, in embodiments, a tube or (micro-) conduit can be used to connect the liquid supply to the main chamber opening. In this way, liquid can flow into the main chamber via the main chamber opening.

[0091] In embodiments, the jetting system can provide energy to the microfluidic device, in particular to the liquid contained within the main chamber. In embodiments, energy can be supplied to the liquid in a variety of different ways. In embodiments, the main chamber, in particular the region close to the second chamber end, can be heated by a heating system, which can comprise a laser, a gas burner, an electrical resistance heater, etc. Further, in embodiments, the chamber wall can also be heated by a thermal heater or a (high temperature) heating element.

[0092] Further, in embodiments, heat can be provided by light (or laser) radiation. I.e. by directing a laser beam onto the chamber wall, in particular in the region close to the second chamber end. In particular, the laser radiation can comprise infrared laser pulses. Alternatively, in embodiments, the laser radiation can be provided at one end of an optical fiber, such that the laser radiation is transmitted (by total internal reflection) to the other end of the optical fiber, wherein the other end of the optical fiber is attached to or configured in the vicinity of the chamber wall, in particular the second chamber end. In embodiments, the chamber wall can be transmissive for the light radiation. Thus, in this way, energy can be provided to the liquid by light (or laser) radiation. In particular, the wavelength of the provided (laser) radiation can be chosen from the range of 200 - 11000 nm, such as from the range of 300 - 8000 nm, in particular from the range of 400 - 3000 nm. Additionally or alternatively, in some embodiments, the chamber wall can comprise a thermal coating (applied to the outside of the chamber wall). In particular, the thermal coating can be heated by the light (or laser) radiation and conduct heat via the chamber wall to the liquid. Typically, in some embodiments, the provided energy can be in the range of 0.01 - 50 mJ.

[0093] Alternatively, in embodiments, mechanical energy can be provided to the liquid. For example, in some embodiments, the second chamber end can comprise a second chamber opening. In particular, a piston can be configured within the main chamber (and extend into the main chamber via the second chamber opening), such that the piston can be moved along the device longitudinal axis (A D) driven. Thus, in this way, the piston can be advanced to advance the liquid in the main chamber. In particular, the piston can have a size equal to the (inner) size of the main chamber, such that the liquid does not flow upstream of the piston upon advancement of the piston. In embodiments, the piston can have a height (H T ) wherein H T may be chosen from the range of 1 - 1000 pm, in particular from the range of 2 - 500 pm, such as from the range of 5 - 400 pm, in particular from the range of 10 - 200 pm. Further, in embodiments, the piston can have a width (W T ) wherein W T may be chosen from the range of 1 * H T - 20 * H T , for example from the range of 2 * H T - 10 * H T , in particular from the range of 4 * H T - 8 * H T , more in particular from the range of 5 * H T - 7 * H T . In embodiments, the piston can be driven by a compression spring configured outside the main chamber (or, in some embodiments, inside the second chamber end). The spring can in particular be compressed and, upon release, can drive the piston in a downstream direction. Further, in embodiments, the piston can be driven by a (pressurized) gas. In particular, a pressurized gas can be supplied upstream of the piston, the expansion of the gas can drive the piston in a downstream direction.

[0094] In embodiments, a piezoelectric actuator can be used for the jetting. In particular, the microfluidic device can comprise a piezoelectric actuator configured to provide (mechanical) energy to the liquid. In particular, in embodiments, the piston (see above) can comprise a piezoelectric actuator.

[0095] Alternatively, in embodiments, the main chamber (in the absence of a piston) can be provided with a pressurized gas. In particular, the chamber wall can comprise a second main chamber opening. In particular, the second main chamber opening can be located at a distance L o2 from the second chamber end. In embodiments, L02may be chosen from the range of 10 - 2000 pm, such as from the range of 100 - 1500 pm, in particular from the range of 500 - 1000 pm. Further, in embodiments, the second main chamber opening can have a diameter D o2 . In particular, D o2may be selected from the range of 1 - 500 pm, such as from the range of 5 - 250 pm, in particular from the range of 10 - 100 pm. In embodiments, the main chamber can be fluidically coupled to a gas supply, i.e. in embodiments, the gas supply can be configured to provide (pressurized) gas to the main chamber via the second main chamber opening. Thus, in embodiments, a tube or (micro-) conduit can be used to connect the gas supply to the second main chamber opening. The pressurized gas can flow into the main chamber, in particular at a position close to the second chamber end. In particular, the pressurized gas can expand, thereby forcing the liquid to flow in a downstream direction along the device longitudinal axis (A D ) and thereby ejecting a microfluidic jet.

[0096] Thus, in this way, the liquid can be supplied with energy in a variety of different ways (e.g. thermal, mechanical, optical, etc.).

[0097] In further embodiments, the jet ejection system can comprise a control system. In particular, the control system can be configured to control (or operate) the jet ejection system. In particular, the control system can control the filling of the liquid in the main chamber. I.e. in embodiments, the control system can regulate the flow of liquid from the liquid supply to the main chamber. Further, the control system can also regulate the energy provided to the liquid in the main chamber. For example, the control system can regulate the gas pressure provided to the embodiments of the microfluidic device. Or, in embodiments, the control system can regulate the power of a laser-based radiation system. Thus, in this way, the control system can in particular control the operation of the jet ejection system.

[0098] “Control” and similar terms herein can in particular at least refer to supervising the operation of the ejection system. Thus, “control” and similar terms herein can refer to supervising the operation of the ejection system or of one or more elements comprised by the ejection system. The control of the elements can be done by a control system. Thus, the control system and the elements can be at least temporarily or permanently functionally coupled. The elements can comprise the control system. In embodiments, the control system and the elements can not (necessarily) be physically coupled.

[0099] The control can be done via wired and / or wireless means. The term “control system” can also refer to a plurality of different control systems, in particular to functionally coupled control systems, and for example, wherein one master control system can act as a master control system and one or more other control systems can act as slave control systems. In embodiments, the control system can be operated via a user interface, but other options, e.g. performing operations according to (external) sensor signals or (temporal) schemes, are also possible.

[0100] In another aspect, the present application can provide a method of ejecting a jet using a microfluidic device. In embodiments, the method can comprise a liquid supply step comprising providing a liquid to a main chamber. In particular, the liquid supply step can comprise filling the main chamber with 20-70 vol.% of the liquid. In embodiments, the method can further comprise an ejection step comprising providing radiation to the chamber wall and / or the liquid such that at least a portion of the liquid is boiled and a jet of liquid is ejected.

[0101] Thus, in particular embodiments, the present application can provide a method of ejecting a jet using a microfluidic device, wherein the method comprises a liquid supply step comprising providing a liquid to a main chamber, wherein the liquid supply step comprises filling the main chamber with 20-70 vol.% of the liquid, wherein the method comprises an ejection step comprising providing radiation to the chamber wall and / or the liquid such that at least a portion of the liquid is boiled and a jet of liquid is ejected.

[0102] As mentioned above, the amount of liquid filled in the main chamber can affect the stability and reproducibility of the microfluidic jet ejected by the system. In particular, the volume of the main chamber filled with the liquid can depend on the configuration of the pattern comprised by the chamber wall. That is, depending on the configuration of one or more patches (or groups of patches) comprised by the pattern, the volume percentage of the main chamber filled with the liquid can vary. In embodiments, the liquid supply step can comprise filling 10-80 vol.% of the main chamber (volume) with the liquid, such as 20-70 vol.%, in particular 30-60 vol.%, more in particular 40-50 vol.%.

[0103] Further, in embodiments, the method can comprise an ejection step. In embodiments, the ejection step can comprise providing radiation to the chamber wall and / or the liquid. In embodiments, the radiation can be provided by a laser-based light source.

[0104] As mentioned above, in embodiments, the chamber wall can be transmissive for optical radiation. Thus, energy can be provided to the liquid by optical (or laser) radiation. In particular, the liquid can absorb the (optical) energy and be heated. More in particular, part of the liquid can be brought to boil (or vaporize) forming bubbles, wherein the expanding bubbles contribute to the ejection of the liquid. Additionally or alternatively, a laser can be focused on a portion of the chamber wall, wherein heat can be conducted to the liquid via the chamber wall. In particular, the chamber wall can comprise a thermal coating, wherein the thermal coating contributes to the heat conduction to the liquid. Thus, the method can in particular comprise focusing a laser on a portion of the chamber wall that is closer to the second chamber end than to the first end. Further, in embodiments, an optical fiber can be used, wherein a laser can be directed incident on one end of the optical fiber and transmitted through total internal reflection to the other end of the optical fiber, which can be in contact with or arranged in the vicinity of the chamber wall. Thus, in this way, laser-based radiation can be provided to the liquid. In embodiments, radiation can be provided to the chamber wall and / or the liquid such that at least part of the liquid is brought to boil (and / or vaporize) and ejects a liquid jet.

[0105] Alternatively, in embodiments, the method can comprise an ejecting step, wherein mechanical energy can be provided to the liquid. In particular, the method can comprise driving a piston arranged within the main chamber. In embodiments, the method can comprise driving the piston by a compression spring arranged outside (or in some embodiments within) the main chamber. The method can in particular comprise releasing (the compression) spring, thereby driving the piston in a downstream direction. Further, in embodiments, the method can comprise driving the piston by providing (pressurized) gas upstream of the piston. In particular, the expansion of the gas can drive the piston in a downstream direction.

[0106] Alternatively, in embodiments, the method, in particular the ejecting step, can comprise providing pressurized gas to the main chamber (even in the absence of a piston). In particular, the (pressurized) gas can flow from a gas supply into the main chamber, thereby forcing the liquid to move along the device longitudinal axis (A D ) and thereby eject a microfluidic jet.

[0107] As mentioned above, the ejecting step can comprise bringing part of the liquid to boil and / or vaporize by heating the liquid (in the main chamber). In particular, the heating power can be selected from the range of 0.10 - 10 W, such as from the range of 0.15 - 8 W, in particular from the range of 0.20 - 5 W, more in particular from the range of 0.25 - 1.5 W.

[0108] Spraying systems and methods are known in the art. For example, the method of the present invention can be performed by spraying a liquid jet onto a target material using the system described in WO2020182665, which is hereby incorporated by reference.

[0109] It is noted that the target material can in particular be a viscoelastic material, i.e. a material that exhibits both elastic and viscous behavior when deformed. For example, in embodiments, the target material can comprise a polymer. In further embodiments, the target material can comprise (ex vivo) soft tissue, such as (ex vivo) skin, or (ex vivo) eye. In further embodiments, the target material can comprise a hydrogel, such as one or more of gelatin, agarose, and polyacrylamide. Gelatin and agarose are commonly used to impart texture to food substances, and can also be used as skin substitutes. For example, polyacrylamide can be used to study cell durotaxis (the ability of cells to move in a matrix with a stiffness gradient). In further embodiments, the target material can comprise an artificially manufactured tissue or biomaterial, such as a dermal substitute or a cell culture tissue for implantation, e.g. 3D-printed tissues and organs.

[0110] Hence, in embodiments, the target material can be non-living. Moreover, in embodiments, the method can be a non-medical method.

[0111] In further embodiments, the target material can comprise tissue, such as skin tissue or eye tissue, in particular of a subject.

[0112] In embodiments, the method can comprise spraying a liquid, in particular a liquid jet, at a spray speed selected from the range of 1-250 m / s, such as selected from the range of 2-150 m / s, in particular selected from the range of 5-70 m / s. The liquid jet can in particular be incident on a target comprising the target material. It will be understood by the skilled person that a suitable spray speed can depend on the spray characteristics of the liquid jet, such as the spray diameter, the spray volume, and / or the spray angle (with the target material). Typically, the spray speed of the liquid jet can be (relatively) stable from the moment of spraying to the moment of impact on the target material. However, the spray speed mentioned herein can in particular refer to the spray speed before the liquid jet impacts the target material.

[0113] In further embodiments, the method can comprise ejecting the liquid jet with an ejection volume selected from the range of < 500 μΙ, such as < 200 μΙ, in particular < 100 μΙ. In further embodiments, the liquid jet can be ejected with an ejection volume selected from the range of < 10 μΙ, such as < 5 μΙ, in particular < 1 μΙ. In further embodiments, the liquid jet can be ejected with an ejection volume selected from the range of 2 - 50 nl, such as selected from the range of 5 - 25 nl, in particular selected from the range of 8 - 13 nl. In particular, a (relatively) low ejection volume can be selected to avoid accumulation of liquid on the target material. Thus, in further embodiments, the jet volume of the liquid jet can be selected from the range of < 75 nl, such as from the range of < 50 nl, in particular from the range of < 40 nl. In further embodiments, the jet volume of the liquid jet can be selected from the range of < 30 nl, such as from the range of < 20 nl, in particular from the range of < 15 nl.

[0114] In further embodiments, the method can comprise ejecting the liquid jet with a circular equivalent (jet) diameter selected from the range of 20 μιη - 5 mm, such as 30 μιη - 3 mm, in particular 50 μιη - 1 mm. In embodiments, the circular equivalent diameter can be < 3 mm, such as < 1 mm, in particular < 500 μιη, such as < 100 μιη. The equivalent circle diameter (or ECD) (or "circular equivalent diameter") of a (irregularly shaped) two-dimensional shape is the diameter of a circle that has the same area. For example, the equivalent circle diameter of a square with side length a is 2*a*SQRT(l / π). For a circle, the diameter is the same as the equivalent circle diameter. If a circle with diameter D in the xy-plane is deformed into any other shape (in the xy-plane) without changing the size of the area, the equivalent circle diameter of that shape is D.

[0115] Generally, the liquid jet can be provided perpendicular to the target material, i.e. the liquid jet can travel along a path that is (substantially) perpendicular to the target material before impinging on the target material. In further embodiments, the jet can be provided at an (ejection) angle, wherein the ejection angle is the angle formed with the surface of the target material when the jet impinges on the target material. In embodiments, the liquid jet can be ejected towards the target material at an (ejection) angle of 45° - 90° (relative to the target material), such as at an angle of 60° - 90°, in particular at an angle of 75° - 90°, such as at an angle of 85° - 90°, in particular at an (substantially) 90°. In embodiments, the method can comprise providing the liquid jet to the target material at an angle of 30° - 85° (relative to the target material), such as at an angle of 45° - 80°, in particular at an angle of 50° - 75°.

[0116] Furthermore, in embodiments, the method may include varying (over time) the spray characteristics of the liquid jet. For example, the method may include varying the (circular or spherical equivalent) diameter or spray velocity of the liquid jet over time. In particular, in embodiments, the method may include varying one or more of the spray velocity, (circular or spherical equivalent) diameter, and spray angle (relative to the target material) of the liquid jet.

[0117] As described above, a plurality of continuously provided droplets can be considered a liquid jet. In particular, in embodiments, the method may comprise providing a liquid jet, wherein the liquid jet may comprise one or more (continuously provided) droplets. In further embodiments, the (liquid) droplets may be ejected with a spherical equivalent diameter selected from the range of 30 μm to 3 mm, such as the range of 50 μm to 2 mm, and in particular the range of 100 μm to 1 mm. The equivalent spherical diameter (or ESD) of an (irregularly shaped) three-dimensional shape (or "spherical equivalent diameter") is the diameter of a sphere of equivalent volume. For a sphere, this diameter is the same as the equivalent spherical diameter. If a sphere with a diameter D in the xyz plane can be deformed into any other shape (still in the xyz plane) without changing its volume, then the equivalent spherical diameter of that shape is D.

[0118] Furthermore, in embodiments, (the droplets in) the plurality of droplets may be provided at intervals (independently) selected from the range of 0.02-10 ms, such as from the range of 0.05-5 ms, in particular from the range of 0.1-2 ms. Thus, in embodiments, the method may comprise providing the plurality of droplets at a frequency selected from the range of 0.001-50 kHz, such as from the range of 0.1-50 kHz, or from the range of 1-30 kHz.

[0119] In particular, in embodiments, the method may comprise changing properties of two or more droplets of the plurality of droplets, such as by changing the properties of the droplets continuously (in particular linearly), or such as by changing the properties of the droplets step-wise (e.g., droplets having (approximately) a first set of properties followed by droplets having a second set of properties).

[0120] Thus, in embodiments, the method can comprise varying the ejection properties of the liquid ejection by varying (in time) the ejection properties along the plurality of (continuously provided) droplets. In further embodiments, the method can comprise varying the spacing between two or more consecutive droplets of the plurality of droplets, i.e. the duration of the two or more consecutive intervals can be different. In particular, the method can comprise varying (in time) the frequency at which the plurality of droplets is provided. In particular, in embodiments, the method can comprise varying the frequency in the range of 0.1 - 50 kHz. In further embodiments, the method can comprise providing a frequency sweep, such as in the range of 0.001 - 50 kHz, such as in the range of 0.1 - 50 kHz, in particular in the range of 1 - 30 kHz. The term "frequency sweep" particularly refers herein to starting from a first frequency, continuously or stepwise adjusting the frequency until a final frequency is reached, and optionally (continuously or stepwise) returning to the starting frequency.

[0121] The embodiments described herein are not limited to a single aspect of the application. For example, embodiments describing the method can for example further relate to the system, in particular to an operating mode of the system, or in particular to a control system. Similarly, system embodiments describing the operation of the system can further relate to embodiments of the method. In particular, method embodiments describing the (system) operation can indicate that the system can be configured for and / or suitable for the operation in embodiments. Similarly, system embodiments describing operating mode (phase) actions can indicate that the method can comprise these actions in embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0122] Embodiments of the application will now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1A — Figure 1C Embodiments of a microfluidic device 1 are schematically illustrated, Figure 2A Different shapes of patch areas 200 in embodiments are schematically illustrated, Figure 2B and Figure 2C Symmetry planes 150 of a pattern 300 in embodiments are schematically illustrated, Figure 3 Patterns 300 comprising multiple sets of patch areas 200 in embodiments are schematically illustrated, Figure 4 Embodiments of a fluidic ejection system 1000 are schematically illustrated. The schematic drawings are not necessarily drawn to scale. DETAILED DESCRIPTION

[0123] Figure 1A — Figure 1C Embodiments of a microfluidic device 1 are schematically illustrated. Figure 1A A microfluidic device 1 is shown in a longitudinal axis A of the device DCross-sectional view on a cross-section parallel to the device longitudinal axis A. Figure 1B Isometric view showing another embodiment of a microfluidic device 1 ; Figure 1C Isometric view showing another embodiment of a microfluidic device 1 in a cross-section perpendicular to the device longitudinal axis A D Cross-sectional view on a cross-section perpendicular to the device longitudinal axis A.

[0124] In embodiments, the present invention can provide a microfluidic device 1 for jetting. In embodiments, the microfluidic device 1 can comprise a main chamber 100 defined by a chamber wall 110. In particular, the main chamber 100 can be configured to contain a liquid 10. In embodiments, along the device longitudinal axis A D , the main chamber 100 can have a chamber length L c defined by a first chamber end 101 and a second chamber end 102. It is noted that, in embodiments, the chamber wall 110 can comprise the first chamber end 101 and the second chamber end 102. In particular, the first chamber end 101 can comprise a first chamber opening 1011 for jetting from the main chamber 100. In the shown embodiment, i.e., in Figure 1A — Figure 1C , the first chamber opening 1011 is as large as the first chamber end 101. However, in other embodiments, the first chamber opening 1011 can be (only) a part of the first chamber end 101.

[0125] In particular, in embodiments, the first chamber end can be (completely) open. In particular, the main chamber 100 has an average area S D in a cross-section perpendicular to the device longitudinal axis A H , and the opening area of the first chamber opening (in a plane perpendicular to the device longitudinal axis A D ) can be chosen from the range of 0.5 * S H — S H , in particular from the range of 0.9 * S H — S H , e.g., (substantially) S H .

[0126] In embodiments, the chamber wall 110 can comprise a (surface) pattern 300 of a first (repellent) surface material 111 and a second (affine) surface material 112. In particular, the first surface material 111 can have an equilibrium contact angle θ1> 90° for the liquid 10, and the second surface material 112 can have an equilibrium contact angle θ2for the liquid 10. More particularly, θ1— θ2≥ 20°.

[0127] In embodiments, the (surface) pattern 300 can comprise (surface) patches 200. In embodiments, a patch 200 can be a two-dimensional shape defined on the surface of the chamber wall 110. In embodiments, a patch can have a patch border 205 (see Figure 2A ). Further, in embodiments, a patch 200 can comprise one of the first surface material 111 and the second surface material 112. Further, in embodiments, at least 50% of the patch border 205 can be in contact with the other one of the first surface material 111 and the second surface material 112. In embodiments, a patch 200 can comprise the first surface material 111 and at least 80% of the patch border 205 can be in contact with the second surface material 112. Further, in embodiments, a patch 200 can comprise the second surface material 112 and at least 80% of the patch border 205 can be in contact with the first surface material 111. In further embodiments, a patch can be in contact with the other one of the first surface material 111 and the second surface material 112 along more than 99% of the patch border 205. Generally, in embodiments, a patch 200 can be configured away from the first chamber end 101 (such as in the embodiments shown in Figure 1A and Figure 1B ). In such embodiments, a patch 200 can be completely surrounded by the other one of the first surface material 111 and the second surface material 112. Accordingly, in such embodiments, at least 99% or (even) 100% of the patch border 205 can be in contact with the other one of the first surface material 111 and the second surface material 112. However, in other embodiments, a patch 200 can be configured such that the patch border 205 coincides with the first chamber opening 1011. In such embodiments, only a portion of the patch 200 can be surrounded by the other one of the first surface material 111 and the second surface material 112. Accordingly, in such embodiments, at least 50%, such as at least 60%, in particular at least 70%, more particularly at least 80% of the patch border 205 can be in contact with the other one of the first surface material 111 and the second surface material 112.

[0128] It is noted that, in embodiments, a pattern 300 can comprise (also) a plurality of patches 200. In the embodiment shown in Figure 1A only one patch 200 is visible. Figure 1B and Figure 1C show two and four patches 200, respectively.

[0129] In embodiments, the chamber wall 110 can have a (wall) surface area S w . In particular, a (surface) patch 200 has a (patch) surface area S P . More particularly, 10 -4 ≤ S P / S w ≤2*10 -1 .

[0130] In embodiments, the patch 200 can have a patch longitudinal axis A P . In particular, the patch 200 can have a patch length L P (see also Figure 2A ) along the patch longitudinal axis A P and a patch width W P perpendicular to the patch longitudinal axis A P . In embodiments, the patch width W P may be measured along the chamber wall 110. In particular, L P ≥ 1.5 * W P . In embodiments shown in Figure 1A and Figure 1B , the patch longitudinal axis A P may be perpendicular to the device longitudinal axis A D .

[0131] In embodiments, the patch shape of the patch 200 can approximate a shape selected from a triangle, a trapezoid, in particular a rectangle, a crescent, an ellipse, a circle. In embodiments, the patch shape can approximate a triangle. In further embodiments, the patch shape can approximate a trapezoid. Further, in embodiments, the patch shape can approximate a rectangle. In other embodiments, the patch shape can approximate a crescent. In particular, the patch shape can approximate an ellipse. More particularly, the patch shape can approximate a circle.

[0132] In further embodiments, the patch shape can resemble the above-mentioned shapes, however, the curvature of one or more edges of the above-mentioned shapes can be different. For example, the patch shape can be a triangle-like shape, wherein the patch shape can be a triangle with one curved edge. Thus, in this way, the patch shape can approximate a shape selected from a triangle, a trapezoid (in particular a rectangle), a crescent, an ellipse, a circle, etc. In embodiments, the contour of the patch 200 can be defined by a plurality of line segments, wherein at most two line segments are curved. Figure 2A Various different patch shapes in embodiments are shown.

[0133] "Approximate" and variants thereof, such as "approximating a shape", in the present text means almost identical, in particular identical, to the following terms, e.g. almost identical to a sector or a semi-cylinder. For example, the tile border 205 can delimit a circular tile 200 with minor imperfections. Similarly, for example, the circular shape assumed by the tile 200 can not be a perfect circle, but slightly elliptical. In particular, an object approximating a first shape can in the present text mean that the first shape realization of the object is realized, wherein the first shape realization is defined as the smallest containing shape of the (2D or 3D, respectively) object, wherein the first shape realization has the shape of the first shape, wherein the ratio of the area (volume) of the first shape realization to the area (volume) of the object is < 1.2, in particular < 1.1, such as < 1.05, in particular < 1.02. For example, the tile 200 can approximate a semi-cylinder, wherein the first shape realization can be defined as the smallest containing semi-cylinder of the tile 200, wherein the ratio of the volume of the first shape realization to the volume of the tile 200 is < 1.2, in particular < 1.1, such as < 1.05, in particular < 1.02, including 1. In addition, if a dimension of the first shape is defined, the term "approximate" can mean that the object and the first shape are superimposable (in 2D or 3D, respectively), such that the intersection between the object and the first shape covers at least n% of the object and at least n% of the shape, wherein n is at least 90%, such as at least 95%, in particular at least 98%, such as at least 99%, including 100%.

[0134] In embodiments, the tile 200 can comprise a first surface material 111. In particular, the tile longitudinal axis A P may form an angle a > 80° with the device longitudinal axis A D In embodiments, the tile width W P may be chosen from the range of 0.01 * L c - 0.2 * L c .

[0135] In embodiments, the tile 200 can comprise a second surface material 112. In particular, the tile longitudinal axis A P may form an angle a < 30° with the device longitudinal axis A D In embodiments, the tile length L P may be chosen from the range of 0.2 * L c - 0.95 * L c .

[0136] It is noted that the angle a can in particular be the smallest angle between the device longitudinal axis A D and the tile longitudinal axis A P , i.e. there is no difference between -a and +a, both can be considered a.

[0137] In embodiments, the pattern 300 (of the first surface material 111 and the second surface material 112) can have a symmetry plane 150 (see Figure 2B ). In particular, the device longitudinal axis A D may coincide with the symmetry plane 150, or (or in addition) the device longitudinal axis A D may be perpendicular to the symmetry plane 150. Figure 2B and Figure 2C show some embodiments of patterns having a symmetry plane 150.

[0138] In embodiments, in a cross-section perpendicular to the device longitudinal axis A D , the main chamber 100 can have a circumference 115 (or "periphery") with a (chamber) circumferential length P c . It is noted that the circumference 115 is shown in Figure 1C , wherein, for visualization purposes, the extent of the circumference 115 of the chamber wall 110 (in a cross-section perpendicular to the device longitudinal axis A D ) is schematically marked with an additional (closed) line (with arrows at both ends). This is also shown in Figure 2B (I) and Figure 2C (I) in a similar manner. In particular, the patch area 200 can cover a (patch) circumferential length P p along the circumference 115. In embodiments, P p may be chosen from the range of 0.05*P c — 0.25*P c .

[0139] In embodiments, in a cross-section perpendicular to the device longitudinal axis A D , the main chamber 100 has a circumference 115 (or "periphery") with a (chamber) circumferential length P c . In particular, the patch area 200 can cover a (patch) circumferential length P p along the circumference 115. More particularly, P p may be chosen from the range of 0.4*P c — P c .

[0140] In embodiments, the pattern 300 can comprise a plurality of patch areas 200. In particular, the pattern 300 can comprise a plurality of groups of patch areas 200. Figure 3 such embodiments are shown.

[0141] In embodiments, the chamber height H c of the main chamber 100 can be chosen from the range of 5— 400 pm, and the chamber width W c may be chosen from the range of 2*H c — 10*H cSelect within the range, chamber length L c It can be selected from the range of 100-5000 μm. In addition, in an embodiment, along the chamber length L c The cross-sectional shape of the main chamber 100 may be approximately a shape selected from the group consisting of a rounded rectangle, a racetrack shape, and an ellipse.

[0142] Figure 2A The sheet areas 200 of different shapes in the embodiments are schematically shown.

[0143] In an embodiment, the patch 200 may be defined by multiple sides. Embodiment 1 shows a rectangular patch 200 with a length L P Greater than width W P In an embodiment, the vertical axis A of the slice P It may pass through the midpoint of at least one side of the patch 200 .

[0144] In addition, in an embodiment, the two sides of the area 200 can be configured to be parallel to the longitudinal axis A of the area. P It should be noted that the orientation of the slice 200 may affect the heterogeneous surface chemistry of the chamber wall 110. In particular, the slice 200 can be configured to be parallel to the longitudinal axis A of the device. D Embodiment II is similar to embodiment I, but the direction of the sheet area 200 in embodiment II is perpendicular to that in embodiment I.

[0145] exist Figure 2A In the embodiment III, the area 200 comprises a crescent-shaped area 200. Here, the area 200 can be defined in particular by a crescent shape formed by two curves of different radii. It should be noted that, in this embodiment, the area is oriented toward the axis A. O (Area vertical axis A P ) can be specifically defined as passing through the midpoint of the two curves (represented by the dashed line).

[0146] exist Figure 2A In embodiment IV, the patch 200 is in the shape of a half-track. The half-track shape can be defined by two parallel and equal sides and two lines connecting the ends of the parallel sides to form a closed two-dimensional area, wherein one of the two connecting sides is a straight line and the other is a curve. In this embodiment, the patch length L of the patch 200 is P It can be measured along the parallel side direction, and the width of the area W P It can be measured as the distance between two parallel sides (as shown).

[0147] (2D) Shape of the patch's vertical axis A PIn this context, it may particularly be referred to as an axis along the extension direction and passing through the virtual centroid of the (2D) shape (assuming that the (2D) shape has any thickness). In an embodiment, the longitudinal axis A P The midpoint of the shortest side of the smallest possible rectangle that can contain the shape.

[0148] exist Figure 2A In the embodiment V, the area 200 includes three sides. In this embodiment, the vertical axis A of the area P It can be defined as: passing through the midpoint of one of the sides and passing through the intersection of the other two sides. In the embodiment where the area 200 includes an odd number of sides, the area longitudinal axis A P It can be defined as: passing through the midpoint of one of the edges and passing through the intersection of the other two edges opposite to the edge (such as shown in embodiment VI).

[0149] It should be noted that, in embodiments, the patch 200 may (also) have other patch shapes that are similar to shapes selected from triangles, trapezoids, particularly rectangles, crescents, ellipses, circles, etc. Furthermore, in embodiments, the patch 200 may have a wavy shape, wherein, in such embodiments, the patch length L P It can be measured along the same direction as the measurement wavelength, and the slice width W P It can be measured as the distance between the peaks and troughs of the wave shape. In a further embodiment, the patch 200 can have a contour defined by a plurality of line segments. In particular, at most two of the line segments can be curved.

[0150] Figure 2B and Figure 2C Schematically illustrates an embodiment of the symmetry plane 150 of the pattern 300. In an embodiment, the symmetry plane 150 is parallel to the longitudinal axis A of the device. D In vertical cross-section, the main chamber 100 may have a periphery 115 (or "circumference") having a periphery length P c In particular, the patch 200 may cover a perimeter length P along the perimeter 115. p In an embodiment, P p Available from 0.05*P c —0.25*P c In a further embodiment, P p Available from 0.4*P c —P c Select within the range.

[0151] Figure 2B Shown with the device longitudinal axis A DA vertical cross-section, the cross-section comprising a main chamber 100 having a circular (or "rounded") cross-section. Embodiment I comprises a pattern 300 comprising (only) one tile 200. In the illustrated embodiment, the pattern 300 can have one plane of symmetry 150. Likewise, in embodiment II, the pattern 300 comprises two tiles 200. In the illustrated embodiment, the pattern 300 can have two planes of symmetry 150. The planes of symmetry 150 are indicated by dashed lines. In the illustrated embodiment, the pattern 300 can have another plane of symmetry 150, such as the cross-section.

[0152] Figure 2C A vertical cross-section, the cross-section comprising a main chamber 100 having a circular (or "rounded") cross-section. Embodiment I comprises a pattern 300 comprising (only) one tile 200. In the illustrated embodiment, the pattern 300 can have one plane of symmetry 150. Likewise, in embodiment II, the pattern 300 comprises two tiles 200. In the illustrated embodiment, the pattern 300 can have two planes of symmetry 150. The planes of symmetry 150 are indicated by dashed lines. In the illustrated embodiment, the pattern 300 can have another plane of symmetry 150, such as the cross-section. D A vertical cross-section. Here, the chamber walls 110 in embodiments I, II, III and IV comprise one, two, three and four tiles 200, respectively. As in the embodiments in Figure 2B Similar to the embodiments in, the pattern 300 can in some embodiments comprise at least one plane of symmetry 150. For example, the pattern 300 in embodiments I and III comprises (at least) one plane of symmetry 150. The pattern 300 in embodiments II and IV has (at least) two planes of symmetry.

[0153] Figure 3 An embodiment of a pattern 300 comprising a plurality of sets of tiles 200 is schematically illustrated.

[0154] In embodiment I, the pattern 300 comprises a first set 310 of n tiles 200. In particular, n can be at least 2. In embodiment I, n is 3. In embodiments, the n tiles 200 can be arranged (in a direction parallel to the longitudinal axis A D of the device) consecutively (in particular equidistantly) downstream of the second chamber end 102. Furthermore, in embodiments, each tile 200 in the first set 310 can comprise a first surface material 111. Moreover, in embodiments, the tile longitudinal axis A P of each tile 200 in the first set 310 can form an angle a > 80° with the longitudinal axis A D of the device. In the illustrated embodiment, the liquid is filled into the first tile 200 in the first set 310 of n tiles 200.

[0155] In embodiment II, the pattern 300 comprises a second set 320 of k patches 200. In particular, k can be at least 2. In embodiment II, k is 3. It is noted that in embodiments, the pattern 300 can comprise multiple sets of patches 200. For example, in the illustrated embodiment, the pattern 300 comprises a first set 310 of one patch 200 and a second set 320 of three patches 200.

[0156] Further, in embodiments, each patch 200 of the second set 320 can comprise a second surface material 112. In particular, each patch 200 of the second set 320 can be configured at a (shortest) distance to the second chamber end 102, which distance is selected from the range of 0.3*L c — 0.9*L c (measured along the device longitudinal axis A D ). In embodiments, the patch longitudinal axis A P of each patch 200 of the second set 320 can form an angle a with the device longitudinal axis A D of 30°. Additionally or alternatively, in embodiments, the patches 200 of the second set 320 can converge or diverge towards the first chamber end 101.

[0157] As mentioned above, the pattern 300 can comprise multiple sets, wherein each set can comprise multiple patches 200. Embodiment III shows a microfluidic device comprising multiple third sets 330.

[0158] In embodiments, each third set 330 can comprise a set of m patches 200. In embodiments, m is at least 2. Embodiment III comprises two third sets 330 of m patches 200, wherein each third set 330 comprises three patches 200.

[0159] In embodiments, each patch 200 of the third set 330 can comprise a second surface material 112. In particular, the centroid of (all) patches 200 can be placed along an axis A M defined on the chamber wall 110. More particularly, the axis A M can be parallel to the device longitudinal axis A D . In embodiments, the patch longitudinal axis A P of the m patches 200 of the third set 330 can form an angle a with the device longitudinal axis A D of 5°≤ a ≤ 50°. Further, in embodiments, the centroids of two consecutive patches 200 of the third set 330 can be configured at a first distance d1. In particular, d1 can be selected from the range of 0.05* L c — 0.5* L c .

[0160] Furthermore, in embodiments, the axes A of two neighboring third groups 330 M may be arranged at a distance d2. In particular, d2 (measured along a direction perpendicular to the axes A M of the third groups 330 and along the chamber wall 110) can be chosen from the range of 0.2*P c - 0.5*P c In particular, in embodiments, the distance d2 can be chosen such that the third groups 330 are arranged in a staggered manner. Figure 3 In embodiments as shown in (III), the first third group 330 forms a positive angle a, while the second third group 330 forms a negative angle a. Thus, in this way, the plurality of third groups 330 (of the segments 200) can converge (or diverge) towards the first chamber end 101. In particular, in embodiments as shown in (III), the segments 200 of the plurality of third groups 330 can converge towards the first chamber end 101, in particular the segments 200 of different third groups 330 can converge towards the first chamber end 101. Figure 3 In embodiments as shown in (III), the segments 200 of the plurality of third groups 330 can converge towards the first chamber end 101, in particular the segments 200 of different third groups 330 can converge towards the first chamber end 101.

[0161] Figure 4 An embodiment of a fluid ejection system 1000 is schematically shown.

[0162] In another aspect, the present application can provide a fluid ejection system 1000 comprising (i) a microfluidic device 1, (ii) a liquid supply 500, and (iii) a (laser-based) heating system 600. It is noted that, in embodiments, the heating system 600 can facilitate providing energy to the liquid 10 in the main chamber 100. The skilled person will appreciate that, in embodiments, other energy sources can also be used to provide energy to the liquid 10, for example by means of a piston, Joule heating, dielectric breakdown, etc. Some of these embodiments have been further discussed above.

[0163] In embodiments, the main chamber 100 can comprise a main chamber opening 132. Furthermore, in embodiments, the liquid supply 500 (comprising the stored liquid 550) can be configured to provide the liquid 10 to the main chamber 100 via the main chamber opening 132. In particular, a tube or (micro) conduit 510 can be used to connect the liquid supply 500 to the main chamber opening 132. Furthermore, the (laser-based) heating system 600 can be configured to provide (laser) radiation 601 to one or more chamber walls 110 and the liquid 10 in the main chamber 100. In particular, in embodiments, the laser radiation 601 can comprise infrared laser pulses 610.

[0164] In embodiments, the main chamber opening 132 can be located at a distance L o from the second chamber end 102. In embodiments, L oIt can be selected from the range of 10-2000 μm. It should be noted that in some embodiments, the main chamber opening 132 can also be configured in the second chamber end 102, that is, L o = 0. In addition, in an embodiment, the main chamber opening 132 may have a diameter D o In particular, D o Available in the range of 1-1000 μm.

[0165] exist Figure 4 In the embodiment shown, the (laser-based) heating system 600 may be configured to direct a beam of laser radiation 601 onto the liquid 10 via the chamber wall 110. The energy provided by the laser radiation 601 may be particularly absorbed by the liquid 10 in the main chamber 100.

[0166] Furthermore, in embodiments, liquid 10 may be filled to a predetermined volume (via main chamber opening 132 ) in embodiments, wherein the advancement of the liquid meniscus may be retarded by sheet region 200 .

[0167] The heat provided by the laser radiation 601 can evaporate at least a portion of the liquid 10. The expansion of the evaporated liquid 10 can cause the liquid 10 to move along the longitudinal axis A of the device. D As a result, the microfluidic jet 20 can be ejected from the microfluidic device 1 .

[0168] In another aspect, the present invention provides a method for ejecting a jet 20 using a microfluidic device 1. In embodiments, the method may include a liquid supplying step and an ejecting step. In embodiments, the liquid supplying step may include supplying liquid 10 to a main chamber 100. In particular, the liquid supplying step may include filling 20-70 vol.% of the main chamber 100 with liquid 10.

[0169] In embodiments, the spraying step may include providing radiation 601 to the chamber wall 110 and / or the liquid 10, causing at least a portion of the liquid 10 to boil (or vaporize) and eject the liquid jet 20. Furthermore, in embodiments, the spraying step may include vaporizing a portion of the liquid 10 by heating the liquid 10 (in the main chamber 100). In particular, the heat may be provided at a power selected from the range of 0.1-10 W.

[0170] The term "plurality" means two or more. Also, "plurality" and "number" can be used interchangeably. Those skilled in the art will appreciate that the terms "substantially" and "essentially" are used herein to describe

[0171] The term "comprising" also includes embodiments in which the term "comprising" is interpreted as "consisting of". The term "and / or" means one or all of the listed items. For example, the phrase "A and / or B" can mean A, B, or A and B. The term "comprising" can mean "consisting of" in one embodiment, and "comprising at least the defined species and optionally one or more other species" in another embodiment.

[0172] Also, the terms "first", "second", "third", etc. that are used in the description and in the claims are used to distinguish between similar elements and not necessarily in an ordinal sense. It will be understood that these terms are interchangeable under appropriate circumstances and that the embodiments of the application described herein are capable of operating according to other sequences than those described or illustrated herein.

[0173] The apparatus, devices, or systems described herein can include situations in operation. It will be apparent to those skilled in the art that the application is not limited to the method of operation, or the apparatus, devices, or systems in operation.

[0174] The term "further embodiments" and similar terms can refer to embodiments that include features of previously discussed embodiments, but can also refer to alternative embodiments.

[0175] It is noted that the foregoing description of embodiments is not intended to limit the application, and that many alternatives are possible without departing from the scope of the appended claims.

[0176] In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim.

[0177] The use of the verb "comprise" and its conjugations does not exclude the presence of elements other than those stated. Unless the context clearly indicates otherwise, throughout the description and the claims, the words "comprise", "contain", "include" and the like should be understood to be inclusive in a manner that the processes and compositions described contain the stated elements, but are not limited to those elements, unless the context clearly indicates otherwise. That is, the terms "comprising", "including", "containing", and the like, shall be understood to be open-ended and not to exclude the presence of additional elements, steps, or components.

[0178] The article "a" or "an" preceding an element does not exclude the presence of a plurality of such elements.

[0179] The application can be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In the device claim enumerating several means, the several means can be embodied by one and the same item of hardware. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

[0180] The application also provides a control system, which can control the apparatus, device or system, or can carry out the method or process described herein. Furthermore, the application also provides a computer program product, which, when functionally incorporated into a computer of the apparatus, device or system or comprised by the apparatus, device or system, can control one or more controllable elements of the apparatus, device or system.

[0181] The application also applies to a device, apparatus or system comprising one or more of the characteristics described in the description and / or shown in the attached drawings. The application also applies to a method or process comprising one or more of the characteristics described in the description and / or shown in the attached drawings. Furthermore, if a method is described and an embodiment of the method is described, it should be understood that the apparatus, device or system is suitable for, or configured to, carry out (perform) the method or the embodiment of the method.

[0182] The various aspects discussed in this patent application can be used in combination to provide further advantages. Furthermore, the person skilled in the art will understand that embodiments can be combined and more than two embodiments can also be combined. Furthermore, certain features can form the basis for one or more divisional applications.

Claims

1. A microfluidic device (1) for jet ejection, wherein: The microfluidic device (1) comprises a main chamber (100) defined by a chamber wall (110), wherein: The main chamber (100) is configured to contain a liquid (10), wherein along the longitudinal axis (A) of the device D ), the main chamber (100) has a chamber length (L) defined by a first chamber end (101) and a second chamber end (102). c ), wherein the first chamber end (101) comprises a first chamber opening (1011) for ejecting a jet from the main chamber (100); The chamber wall (110) comprises a pattern (300) consisting of a first surface material (111) and a second surface material (112), wherein the equilibrium contact angle θ1 of the first surface material (111) with respect to the liquid (10) is greater than 90°, and the equilibrium contact angle of the second surface material (112) with respect to the liquid (10) is θ2, wherein θ1-θ2 ≥ 20°; The pattern (300) includes a patch (200), wherein the patch has a patch boundary (205), and a) the patch (200) includes one of the first surface material (111) and the second surface material (112), and b) at least 50% of the patch boundary (205) is in contact with the other of the first surface material (111) and the second surface material (112); The chamber wall (110) has a wall surface area S w , wherein the area (200) has an area surface area S P , of which 10 -4 ≤S P / S w ≤2*10 -1 ;and At the same time as the longitudinal axis of the device (A D ) in a vertical cross section, the main chamber (100) has a periphery (115) having a chamber periphery length P c , wherein the area (200) covers the area perimeter length P along the perimeter (115) p , where P p The value range is 0.01*P c —0.5*P c .

2. The microfluidic device (1) according to claim 1, wherein The slice (200) has a slice longitudinal axis (A P ), wherein the sheet area (200) has a longitudinal axis (A P ) of the area length L P and the vertical axis of the slice (A P ) Vertical slice width W P , where L P ≥1.5*W P .

3. The microfluidic device (1) according to claim 2, wherein The sheet area (200) comprises the first surface material (111), wherein the longitudinal axis (A P ) and the longitudinal axis of the device (A D ) the angle α is ≥ 80°, and wherein the width of the slice W P The value range is 0.01*L c —0.2*L c .

4. The microfluidic device (1) according to claim 2, wherein The sheet area (200) comprises the second surface material (112), wherein the longitudinal axis (A P ) and the longitudinal axis of the device (A D ) is ≤30°, and wherein the slice length (L P ) has a value range of 0.2*L c —0.95*L c .

5. The microfluidic device (1) according to any one of the preceding claims, wherein The pattern (300) has a plane of symmetry (150).

6. The microfluidic device (1) according to any one of the preceding claims, wherein P p The value range is 0.05*P c —0.25*P c .

7. The microfluidic device (1) according to any one of the preceding claims, wherein The patch is in contact with the other of the first surface material (111) and the second surface material (112) along more than 99% of the patch boundary, and wherein the patch (200) has a contour defined by a plurality of line segments, of which at most two line segments are curves.

8. The microfluidic device (1) according to any one of claims 2 to 7, wherein: The pattern (300) comprises a first group (310) of n regions (200), wherein n≥2, wherein: The n slice areas (200) are arranged in sequence from the end (102) of the second chamber along the liquid flow direction; Each of the slices (200) in the first group (310) comprises the first surface material (111); the slice longitudinal axis (A) of each of the slices (200) in the first group (310) is P ) and the longitudinal axis of the device (A D )The angle α is ≥80°.

9. The microfluidic device (1) according to any one of claims 2 to 8, wherein: The pattern (300) comprises a second group (320) of k patches (200), where k≥2, and wherein: Each patch (200) in the second group (320) comprises the second surface material (112); The distance between each area (200) in the second group (320) and the end (102) of the second chamber is in the range of 0.3*L c —0.9*L c ; The vertical axis (A) of each slice (200) in the second group (320) P ) and the longitudinal axis of the device (A D )The angle α is ≤30°.

10. The microfluidic device (1) according to claim 9, wherein k=2, and wherein the slices (200) in the second group (320) converge or diverge toward the first chamber end (101).

11. The microfluidic device (1) according to any one of claims 2 to 10, wherein The pattern (300) includes a plurality of third groups (330), wherein: Each third group (330) includes a group of m slices (200), wherein m≥2, wherein each slice (200) in the third group (330) comprises the second surface material (112), wherein the centroid of each slice (200) is along an axis (A) defined on the chamber wall (110) M ), where the axis (A M ) and the longitudinal axis of the device (A D ) are parallel, wherein the longitudinal axes (A) of the m slices (200) in the third group (330) are P ) and the longitudinal axis of the device (A D ) satisfies an angle α formed between 5°≤α≤50°, wherein the distance between the centroids of two consecutive regions (200) in the third group (330) is a first distance d1, and the value range of d1 is 0.05*L c —0.5*L c .

12. The microfluidic device (1) according to claim 11, wherein The axes (A) of the two adjacent third groups (330) M The distance between them is d2, where the value range of d2 is 0.2*P c —0.5*P c .

13. The microfluidic device (1) according to any one of the preceding claims, wherein The main chamber (100) has a chamber height H in the range of 5-400 μm. c , the value range is 2*H c —10*H c The chamber width (W c ) and the chamber length (L) in the range of 100–5000 μm c ), and wherein, along the chamber length (L c ), the main chamber (100) having a cross-sectional shape approximately selected from a rounded rectangle, a stadium shape, and an ellipse.

14. A jet ejection system (1000) comprising i) a microfluidic device (1) according to any one of the preceding claims, ii) a liquid supply device (500) and iii) a heating system (600), wherein: The main chamber (100) includes a main chamber opening (132); The liquid supply device (500) is configured to provide the liquid (10) to the main chamber via the main chamber opening (132); The heating system (600) is configured to provide radiation (601) to one or more of the chamber walls (110) and the liquid (10) in the main chamber (100).

15. A method for ejecting a jet (20) using a microfluidic device (1) according to any one of claims 1 to 13, wherein: The method comprises: A liquid supplying step, comprising supplying the liquid (10) to the main chamber (100), wherein the liquid supplying step comprises filling 20-70 vol.% of the main chamber (100) with the liquid (10). The spraying step comprises providing radiation (601) to the chamber wall (110) and / or the liquid (10) such that at least a portion of the liquid (10) boils and sprays a liquid jet (20).

Images