Soft electronic devices based on particle swallowing effect and their fabrication methods

Abstract

This invention relates to soft electronic devices based on the particle engulfment effect and their fabrication method. The fabrication method includes the following steps: S1, attaching a perforated mask to a polymer substrate, controlling the position of the polymer substrate that can be printed; S2, uniformly dispersing micro / nano particles on the mask, with the micro / nano particles contacting the polymer substrate at the perforations of the mask; S3, after contacting the polymer substrate, the micro / nano particles gradually enter the polymer substrate through the particle engulfment effect, forming a functional composite material; S4, removing the perforated mask to form the soft electronic device. This invention directly prints micro / nano materials in a soft polymer matrix without introducing solvents, avoiding chemical incompatibility and complex hydrodynamic behavior. Utilizing the surface energy-driven particle engulfment phenomenon, deep embedding of materials is achieved spontaneously without the need for additional energy. It enables seamless integration of different materials into high-performance flexible electronic devices. Through multilayer engulfment printing technology, multi-material wireless electronic devices can be created, enabling layered printing.

Description

Technical Field

[0001] This invention relates to the field of flexible electronics technology, specifically to soft electronic devices based on the particle swallowing effect and their fabrication methods. Background Technology

[0002] Soft electronic devices are attracting increasing attention due to their excellent mechanical compatibility with biological tissues and their wide range of applications in health monitoring, medical devices, human-computer interaction, and augmented reality. To realize these applications, it is necessary to develop soft electronic devices with high component density, good mechanical flexibility, and high electronic performance.

[0003] Current methods for manufacturing soft electronic devices typically involve dispersing micro- and nano-materials into soft matter precursors to form processable inks, and then patterning the inks to form functional devices.

[0004] However, the use of inks presents challenges related to complex hydrodynamic behavior and non-orthogonality of component chemistry, limiting the manufacture of high-density, multi-material, and multi-layer devices: insufficient control of surface tension or rheology can cause particle agglomeration or non-uniform deposition, resulting in reduced manufacturing accuracy / performance; multi-material integration can cause incompatibility between chemical components, leading to device deformation or even dissolution; increasing the density of conductive materials in inks can increase conductivity but affects processability and mechanical properties. Summary of the Invention

[0005] In view of the problems existing in the prior art, the purpose of this invention is to provide a soft electronic device based on the particle swallowing effect and a method for its preparation, which can produce high-performance soft electronic devices without the use of solvents.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] The fabrication method of soft electronic devices based on particle swallowing effect includes the following steps:

[0008] S1. Attach the cutout mask to the polymer substrate to control the position of the polymer substrate that can be printed;

[0009] S2. Disperse micro-nanoparticles uniformly on a perforated mask, and let the micro-nanoparticles contact the polymer substrate at the perforations of the perforated mask.

[0010] S3. After micro and nano particles come into contact with the polymer substrate, they gradually enter the polymer substrate through the particle phagocytosis effect, forming a functional composite material.

[0011] S4. Remove the photomask to form a soft electronic device.

[0012] Furthermore, the polymer substrate includes at least one of PDMS, Ecoflex ionogel, and hydrogel.

[0013] Furthermore, Ecoflex ion gel is prepared by mixing Ecoflex gel A with an ionic liquid at a weight ratio of 100:1-20, then adding Ecoflex gel B at a weight ratio of 1-5:1 to Ecoflex gel A and stirring. After degassing the ion gel, it is poured into a Teflon mold and cured at room temperature for 1-5 days.

[0014] Furthermore, by repeating S2-S4, a multi-material, multi-layer soft electronic device is constructed through a layer-by-layer overprinting method.

[0015] Furthermore, multilayer soft electronic devices comprise homogeneous layers made of the same micro / nanoparticle material, with different homogeneous layers achieving the same function.

[0016] Furthermore, multilayer soft electronic devices include heterogeneous layers made of different micro / nanoparticle materials, with different numbers of layers achieving different functions.

[0017] Furthermore, multilayer soft electronic devices include homogeneous layers and heterogeneous layers.

[0018] Furthermore, the perforated mask is a perforated template.

[0019] Furthermore, micro and nanoparticles include zero-dimensional, one-dimensional, or two-dimensional metals, metal oxides, and carbon materials with micrometer or nanometer dimensions.

[0020] The soft electronic device based on the particle swallowing effect was prepared using the above-described method.

[0021] In summary, the present invention has the following advantages:

[0022] 1. Direct printing technology: Directly printing micro / nano materials into a soft polymer matrix without the need for solvents, thus avoiding complex hydrodynamic behavior.

[0023] 2. Particle swallowing phenomenon: The particle swallowing phenomenon driven by surface energy is used to achieve deep embedding of materials. It is generated spontaneously and does not require the introduction of additional energy.

[0024] 3. Compatibility and Integration: Enables seamless integration of different materials into high-performance flexible electronic devices. Through multilayer engulfing printing technology, multi-material wireless electronic devices can be created, achieving layered printing. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the fabrication method of the soft electronic device in this embodiment.

[0026] Figure 2 This is a schematic diagram of template placement in this embodiment.

[0027] Figure 3 This is a particle dispersion diagram for particle engulfment printing technology.

[0028] Figure 4 This is a particle engulfment diagram for particle engulfment printing technology.

[0029] Figure 5 Silica spheres with diameters of 0.3µm, 1µm, 5µm and 20µm were swallowed by the substrate.

[0030] Figure 6 To print carbon nanotube strain sensors on an A4-sized Ecoflex substrate.

[0031] Figure 7 SEM cross-section and EDS image of silver elemental density of printed silver nanoparticles engulfed by particles.

[0032] Figure 8 SEM cross-section and EDS image of aluminum elemental content of printed aluminum nanoparticles engulfed by particles.

[0033] Figure 9 SEM cross-section and EDS image of copper elemental composition for particle engulfment of printed copper nanowires.

[0034] Figure 10 SEM cross-section and EDS image of nickel elemental composition of printed nickel oxide nanoparticles engulfed by particles.

[0035] Figure 11 SEM cross-sectional images of carbon black (a), carbon nanotubes (b), and graphene (c) engulfed on a substrate with a modulus of 20 kPa.

[0036] Figure 12 SEM cross-sectional images of silica particles and copper nanowire heterolayers printed using particle engulfment printing technology.

[0037] Figure 13 Cross-sectional images of the printed silica sphere (top left), after 5000 tensile cycles (top right), and at 100% strain (bottom).

[0038] Figure 14 To print spiral conductive tracks (silver microparticles) on a soft rod (coated with Ecoflex gel).

[0039] Figure 15 The hydrogel (AG2540) engulfs silver microparticles.

[0040] Figure 16 Images of a wireless power supply device with 0% (left) and 100% (right) strain printed on a swallowing pattern.

[0041] Figure 17A printed wireless strain sensor mounted on the index finger.

[0042] Figure 18 A printed RFID strain sensor mounted on the wrist.

[0043] Figure 19 A printed wireless inductive-capacitor resonator mounted on the elbow.

[0044] In the picture:

[0045] 1-Application brush, 2-Perforated masking template, 3-Polymer substrate, 4-Micro / nanoparticles. Detailed Implementation

[0046] The present invention will now be described in further detail.

[0047] A method for fabricating a soft electronic device includes the following steps:

[0048] S1. Template Placement: Align the perforated mask 2 with the polymer substrate 3, leaving a gap to prevent the perforated mask 2 from adhering to the upper surface of the polymer substrate 3. Figure 1 , Figure 2 As shown; where the perforated mask 2 is a perforated template made by laser processing.

[0049] S2. Particle Dispersion: Micro-nanoparticles 4, including but not limited to nanowires and nanoparticles, are placed on the perforated mask 2. Then, a brush 1 is used to cyclically brush the upper surface of the perforated mask 2, allowing the micro-nanoparticles 4 to fall out of the structure of the perforated mask 2 as much as possible. This promotes contact between the micro-nanoparticles 4 and the upper surface of the polymer substrate 3, forming a pre-designed structural pattern, such as... Figure 3 As shown.

[0050] S3. Particle Attack: After the micro / nano particles 4 come into contact with the polymer substrate 3, they gradually enter the substrate under the action of the surface tension of the polymer substrate 3, forming a particle attack effect, such as... Figure 4 As shown.

[0051] S4. Template Removal: Remove the hollowed-out mask template 2. At this time, the micro-nanoparticles 4 are embedded in the polymer substrate 3 to form a functional composite material and obtain the desired soft electronic device.

[0052] In the fabrication of soft electronic devices using existing technologies, micro- and nanomaterials need to be dispersed into soft matter precursors to form processable inks, and then the inks are patterned to form functional devices. The use of inks easily leads to challenges related to complex hydrodynamic behavior and non-orthogonality of component chemistry, including: limited spatial resolution: due to improper control of hydrodynamics such as surface wetting and rheology, the colloidal dispersion and deposition are uneven, which limits the spatial resolution; reduced electronic / mechanical properties: the chemical asymmetry between components can greatly reduce electronic / mechanical properties and lead to geometric deformation or dissolution of the manufactured structure; high manufacturing complexity: it is necessary to prepare uniformly dispersed colloidal suspensions and optimize complex fluid and multiphase colloidal transport phenomena, which increases the complexity and cost of manufacturing.

[0053] This method creatively incorporates micro / nanomaterials directly and heterogeneously into soft, elastic polymers through particle engulfment, eliminating the need to mix solid functional powders with liquid solvents or polymers. This process can even occur spontaneously on a fully formed polymer matrix when the elastic capillary length of the matrix is ​​much greater than the characteristic length of the particles. Particle engulfment can be used to print soft electronic devices with wireless sensing, communication, and power transmission capabilities. Particle engulfment printing enables the seamless integration of previously incompatible material classes, thereby expanding the functionality, performance, and complexity of inherently soft electronic devices.

[0054] Preferably, the polymer substrate 3 is prepared by mixing Ecoflex gel A with an ionic liquid at a weight ratio of 100:1, then adding Ecoflex gel B at a weight ratio of 1:1 to Ecoflex gel A and stirring for 3 minutes to obtain an ionic gel. After degassing the ionic gel, it is poured into a Teflon mold and cured at room temperature for 3 days.

[0055] Preferably, by repeating steps S2 and S3, multi-material, multi-layered soft electronic devices can be constructed through a layer-by-layer overprinting method. The "overprinting" process, where previously engulfed particles are printed onto the substrate, creates a multi-layered particle structure within the soft polymer. The indentation depth increases with the number of overprints, indicating that the previously engulfed particles no longer experience surface tension and are driven deeper into the polymer substrate 3 when a new layer is overprinted. The layer thickness can be controlled using a layer-by-layer printing method.

[0056] Multilayer soft electronic devices can include homogeneous layers made of the same micro / nanoparticle material, with different homogeneous layers achieving the same function.

[0057] Multilayer soft electronic devices can also include heterolayers made of different micro / nanoparticle materials, with different numbers of layers achieving different functions.

[0058] Multilayer soft electronic devices can also include homogeneous layers and heterogeneous layers.

[0059] The soft electronic device based on the particle swallowing effect was prepared using the above-described method.

[0060] Performance testing: Using liquid metal as solder paste, printed soft composite materials are connected to rigid components, and the electrical performance and mechanical stability of the manufactured soft electronic devices are tested.

[0061] like Figure 5 As shown, silica spheres with diameters of 0.3µm, 1µm, 5µm and 20µm were engulfed by the substrate. The Young's modulus E of the substrate spans the range of human tissue, indicating that the particle engulfment printing technology can be applied to substrates with different Young's moduli, spanning the range of Young's modulus of human tissue. Substrates of different strengths can engulf micro and nano particles of different sizes, demonstrating the wide applicability of particle engulfment technology.

[0062] like Figure 6 As shown, a carbon nanotube strain sensor was printed on an A4-sized Ecoflex substrate, demonstrating that particle engulfment printing technology can print devices over a large area, simultaneously printing electronic devices of different patterns and sizes on the same substrate. The different devices depend only on the pattern of the mask.

[0063] like Figure 7 As shown, the SEM cross-section of the particles engulfing printed silver nanoparticles and the EDS image of silver element are shown.

[0064] like Figure 8 As shown, the SEM cross-section and EDS image of aluminum elemental content of the particles engulfing printed aluminum nanoparticles are presented.

[0065] like Figure 9 As shown, the SEM cross-section and EDS image of copper elemental composition of the particle-engulfed printed copper nanowires are displayed.

[0066] like Figure 10 As shown, the SEM cross-section and EDS image of nickel elemental composition of the particles engulfing printed nickel oxide nanoparticles are presented.

[0067] Figures 7-10 This mainly demonstrates the wide applicability of particle engulfment printing technology, which can engulf different micro and nano particles, including nanowires and nanoparticles. The SEM cross-sectional image proves that the micro and nano particles were indeed engulfed by the substrate, and the EDS elemental distribution corresponds to the SEM image.

[0068] Figure 11 The SEM cross-sectional images of carbon black (a), carbon nanotubes (b), and graphene (c) engulfed on a substrate with a modulus of 20 kPa demonstrate that particle engulfment printing technology can engulf different types of carbon materials, including three-dimensional carbon black, one-dimensional carbon nanotubes, and two-dimensional graphene, showcasing the wide applicability of particle engulfment printing technology.

[0069] like Figure 12 As shown, the SEM cross-sectional image of the heterolayer of silica particles and copper nanowires printed by particle engulfment printing technology demonstrates that particle engulfment printing technology can print different numbers of layers and different materials, with clear layering and no mutual interference, and can fabricate heterolayer devices, with different numbers of layers enabling different functions.

[0070] like Figure 13 As shown, the cross-sectional images of the printed silica spheres (top left), after 5000 stretching cycles (top right), and at 100% strain (bottom) illustrate the stability of particle engulfment printing. The silica particles are deeply embedded in the polymer substrate 3. Even at 100% strain, after 5000 stretching cycles, they remain stably embedded in the substrate. The particle engulfment printing technology has stability and resistance to deformation.

[0071] Figure 14 The ability to print helical conductive tracks (silver microparticles) on a soft rod (coated with Ecoflex gel) demonstrates that particle engulfment technology can be used for three-dimensional printing, without being limited by planar space.

[0072] Figure 15 The engulfment of silver microparticles by the hydrogel (AG2540) demonstrates that particle engulfment technology can directly print particles into biocompatible soft matrices, and that micro and nanoparticles can directly bind to biocompatible materials.

[0073] Figure 16 Images of a wireless power supply device with 0% (left) and 100% (right) strain, showing a three-layer structure: an antenna layer (silver microparticles), a dielectric layer (barium titanate microparticles), and a bottom layer (silver microparticles), illustrating the excellent resistance to deformation of devices fabricated using particle engulfment printing technology.

[0074] Figure 17 The printed wireless strain sensor mounted on the index finger illustrates that particle swallowing technology can integrate heterogeneous devices and connect two different materials.

[0075] Figure 18 This demonstrates a printed RFID strain sensor mounted on the wrist, which connects flexible and rigid commercial devices to identify wrist joint movements.

[0076] Figure 19 A printed wireless inductive-capacitive resonator mounted on the elbow has three layers: an antenna layer (silver microparticles), a dielectric layer (barium titanate microparticles), and a bottom layer (silver microparticles). This demonstrates that particle engulfment can print different numbers of micro / nano particles, each with different functions.

[0077] In summary, this invention provides a flexible electronic device and its simple and efficient fabrication method. Based on the particle engulfment effect, without the need for ink, micro- and nano-particles can be directly embedded into a solidified soft material driven by surface energy, forming a stable and deeply embedded functional pattern entirely driven by surface energy. Particle engulfment is essentially a contact behavior between the soft material substrate and the particles. When the length of the elastic capillary of the soft material is much larger than the characteristic size of the particles, the contact interface simulates liquid wetting behavior and spontaneously engulfs the particles. The particle engulfment effect can fundamentally change the fabrication process of flexible electronics, separating the soft material fabrication from the construction of the functional percolation network. Therefore, it can avoid the complex hydrodynamic behavior and chemical non-orthogonality problems faced by ink preparation and its subsequent patterning process, and is expected to open up a new field of flexible electronics manufacturing.

[0078] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A method for fabricating soft electronic devices based on particle swallowing effect, characterized in that: Includes the following steps, S1. Attach the cutout mask to the polymer substrate to control the position of the polymer substrate that can be printed; S2. Disperse micro-nanoparticles uniformly on a perforated mask, and let the micro-nanoparticles contact the polymer substrate at the perforations of the perforated mask. S3. After micro and nano particles come into contact with the polymer substrate, they gradually enter the polymer substrate through the particle phagocytosis effect, forming a functional composite material. S4. Remove the photomask to form a soft electronic device.

2. The preparation method according to claim 1, characterized in that: The polymer substrate includes at least one of PDMS, Ecoflex ionogel and hydrogel.

3. The preparation method according to claim 2, characterized in that: Ecoflex ionomer gel is prepared by mixing Ecoflex gel A with an ionic liquid at a weight ratio of 100:1 to 20, then adding Ecoflex gel B at a weight ratio of 1 to 5:1 with Ecoflex gel A and stirring. After degassing the ionomer gel, it is poured into a Teflon mold and cured at room temperature for 1 to 5 days.

4. The preparation method according to claim 1, characterized in that: Repeat steps S2-S4 to construct multi-material, multi-layer soft electronic devices by layer-by-layer overprinting.

5. The preparation method according to claim 4, characterized in that: Multilayer soft electronic devices consist of homogeneous layers made of the same micro / nanoparticle material, with different homogeneous layers performing the same function.

6. The preparation method according to claim 5, characterized in that: Multilayer soft electronic devices consist of heterogeneous layers made of different micro- and nanoparticle materials, with different numbers of layers achieving different functions.

7. The preparation method according to claim 6, characterized in that: Multilayer soft electronic devices include homogeneous layers and heterogeneous layers.

8. The preparation method according to claim 1, characterized in that: The perforated mask is a perforated template.

9. The preparation method according to claim 1, characterized in that: Micro and nanoparticles include zero-dimensional, one-dimensional, or two-dimensional metals, metal oxides, and carbon materials with micrometer or nanometer dimensions.

10. A soft electronic device based on the particle swallowing effect, characterized in that: It is prepared by the preparation method according to any one of claims 1-9.

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