A light-driven fluid manipulation device and method

Abstract

This invention discloses a light-driven fluid manipulation device and method, belonging to the field of microfluidics and soft robotics. The device includes a carrier platform, an LCE ring mounted on the platform, and blades fixed to the LCE ring. The LCE ring is made of a photothermal responsive liquid crystal elastomer material. Under steady-state illumination, the LCE ring absorbs light energy, generating a non-uniform temperature field and thermally shrinking and deforming, thereby generating torque to achieve continuous self-rotation, synchronously driving the blades to drive the surrounding fluid to flow in a directional manner or to mix in a rotational manner. This invention also provides a control method based on a multi-field coupling model, achieving non-contact precise control of the fluid driving speed by adjusting the external light intensity. This device requires no external power supply or complex mechanical seals and is suitable for applications such as microfluidic chips, biomedical detection, and in-situ water treatment.

Description

Technical Field

[0001] This invention relates to the fields of microfluidics and soft robotics, and more specifically, to a light-driven fluid manipulation device and method. Background Technology

[0002] In cutting-edge technology fields such as microfluidic chips, in-situ treatment of environmental water bodies, and biomedical aseptic detection, achieving contactless, cableless, and precise fluid drive is the core requirement for the development of current equipment technology. Traditional fluid drive systems, such as industrial micro pumps or magnetic stirrers, generally rely on external industrial power supplies, built-in electromagnetic winding motors, or complex pneumatic pipelines for control. They have inherent defects such as complex overall structure, easy wear of dynamic seals leading to the introduction of particulate or bacterial contamination, and difficulty in stable operation in highly sealed or strictly aseptic environments.

[0003] In recent years, various stimulus-responsive materials, especially liquid crystal elastomers (LCEs) with photothermal response properties, have been used by academia and industry to construct soft actuators because they can directly convert environmental energy such as light and heat energy, which can be easily projected remotely, into programmable macroscopic mechanical deformation. However, most of the existing research on actuators based on LCE materials focuses only on realizing the rotation, rolling, or swimming displacement of the soft robot itself. The cross-domain application research of efficiently converting its physical deformation into continuous directional driving of external fluid media and directly using it as a power "blade" or "impeller" to pump fluid is still in its infancy. Therefore, designing an innovative device with a simplified mechanical structure, no need for external wired power supply, and the ability to achieve non-contact and safe fluid manipulation, and establishing a rigorous light-heat-force-fluid coupling prediction model, has become the key to breaking through the current bottleneck of microfluidic manipulation technology. Summary of the Invention

[0004] The present invention aims to solve the technical problems of existing fluid drive systems that are highly dependent on external power supply, have complex and redundant electromechanical structures, and are difficult to achieve non-contact remote fluid control in special closed working conditions.

[0005] To address the aforementioned problems, the present invention provides a light-driven fluid manipulation device, comprising: a carrier platform; an LCE ring disposed on the carrier platform, the LCE ring being made of a photothermal responsive liquid crystal elastomer material and configured to undergo thermal deformation and self-rotation under steady-state illumination; and blades fixedly connected to the LCE ring, configured such that when the liquid crystal elastomer ring self-rotates under illumination, the blades rotate accordingly and drive the surrounding fluid to generate directional flow.

[0006] The optically driven fluid manipulation device provided by this invention has, but is not limited to, the following beneficial effects compared to the prior art: Addressing the technical challenges of existing fluid drive systems—high reliance on external power supplies, complex and redundant electromechanical structures, and difficulty in achieving non-contact remote fluid control under enclosed and special working conditions—this device's basic hardware architecture includes a carrier platform serving as a support base, an LCE ring as the core energy conversion component, and impellers as the fluid work output component. The LCE ring is made of a main-chain or side-chain photothermal responsive liquid crystal elastomer polymer material containing azobenzene or similar photoisomerization groups. It is suspended on the carrier platform in a freely rotatable state by a central support shaft or limiting guide rail. The principle is that when a vertically downward, steady-state light-emitting diode parallel beam shines on the outer surface of the LCE ring, the polymer liquid crystal units on the light-receiving side absorb photon energy, generating a non-uniform localized heating phenomenon. This causes a thermodynamic phase transition from a nematic phase to an isotropic phase within the material's internal lattice, inducing macroscopic thermal shrinkage deformation. Due to the asymmetry of this thermal shrinkage deformation on the ring-shaped topology, the LCE ring internally generates… The tangential internal stress difference generates a mechanical driving torque that causes the ring to continuously tumble and rotate around its geometric central axis. Simultaneously, the root end face of the impeller is fixedly connected to the outer wall of the LCE ring. When the LCE ring begins to spin smoothly under light-induced illumination, its mechanical torque is transmitted to the impeller without loss, driving the impeller to rotate synchronously in the fluid medium. The impeller then uses its water-facing surface to push and shear the water, overcoming the fluid's viscous damping force and converting microscopic thermomechanical energy into macroscopic fluid kinetic energy. This generates a non-contact directional flow or stirring flow field. This structure directly eliminates the motor rotor, transmission gear set, and dynamic seal structure found in traditional pumps. It is easy to manufacture, miniaturize at the chip level, and mass-produce at low cost. It only requires external steady-state parallel light to continuously drive the fluid, without the need for any physical wires, external power supply, or electromagnetic controller, thus avoiding the risks of electrical short circuits and seal leaks. It is particularly suitable for special fluid control environments that are closed, sterile, toxic, or difficult to wire, resulting in better performance.

[0007] Furthermore, the LCE ring is formed by bending a liquid crystal elastomer straight rod into a ring and fixing it. The overall cross-section of the LCE ring is a circular structure. The number of blades is two or more, and they are distributed at equal distances along the circumference of the LCE ring.

[0008] Furthermore, the blades are configured to achieve multi-mode motion by changing their combined layout on the carrier platform. When the blades are arranged symmetrically, the fluid is propelled in a straight line. When the blades are arranged in an anti-symmetrical staggered manner, the fluid is stirred in a rotating manner.

[0009] The present invention also provides a control method for a light-driven fluid manipulation device, comprising the following steps: S1: Establish a multi-field coupled model of light-heat-force-fluid to determine the mapping relationship between light intensity parameters and fluid driving velocity; S2: Non-contact control of fluid drive speed is achieved by remotely adjusting the light intensity acting on the LCE ring.

[0010] Furthermore, the specific steps for establishing the optical-thermal-mechanical-fluid multi-field coupling model in S1 include: S11: Establish a spatial temperature field distribution model of the LCE ring cross section under steady-state illumination, considering photothermal input, thermal relaxation and rotational effects, and obtain the temperature distribution law; S12: Based on the obtained temperature field distribution law, calculate the thermal strain, elastic strain, and cross-sectional normal stress, and integrate to obtain the stress around the cross-section. The driving torque of the shaft is determined, and the relationship between the driving torque and the photothermal power, the coefficient of contraction, and the angular velocity is clarified. S13: Based on the driving torque generated by the aforementioned calculations, the balance equations for blade rotation, system rotation, and water flow propulsion are derived and dimensionless to improve the model's applicability and computational stability.

[0011] Furthermore, the temperature field distribution model of the LCE ring cross section under steady-state illumination in S11 is obtained by solving the energy conservation equation, which is as follows: ; in, Represents the coordinates of any point on the cross-section of the LCE ring. Radial coordinates, R is the circumferential angle, and R represents the radius of the LCE ring. This represents the characteristic thermal relaxation time of the LCE ring cross section. Indicates the rotational angular velocity. Indicates the equivalent photothermal rate. This represents the uniform offset of the temperature field.

[0012] Furthermore, the thermal strain in S12 Elastic strain and the normal stress on the LCE ring section The calculation equation is as follows: ; ; ; in Indicates the shrinkage coefficient. Indicates the elastic modulus. This represents the average axial strain. This represents static strain.

[0013] Furthermore, in S12, LCE surrounds The calculation equations for the driving torque of the shaft and the driving torque of the LCE ring itself are as follows: ; ; in, This represents the radius of the LCE rod's cross-section. This is expressed as the area of ​​each tiny unit in the polar coordinate system of the LCE ring cross section. Stress on the surface.

[0014] Furthermore, the specific balance equations for the blade rotation, system rotation, and water propulsion in S13 are as follows: The equation for the blade angular velocity is: ; The system's rotational angular velocity equation is: ; The equation for water propulsion velocity is: ; in, Let be the rotational damping coefficient of the blade. The length of the blade, The forward damping coefficient is... Let be the system rotational damping coefficient. The lever arm is the distance between the two blades.

[0015] Furthermore, the specific calculation formula after dimensionless processing in S13 is as follows: The temperature field is dimensionless. ; The driving torque is dimensionless. ; The dimensionless angular velocity of the propeller blades is transformed into ; The system rotational speed is dimensionless. ; The propulsion speed is dimensionless. ; in, , , , , , , , , , , , , The ambient temperature. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of a linear propulsion mode of fluid in a light-driven fluid manipulation device according to an embodiment of the present invention; Figure 2 This is a schematic diagram of a structure in which the fluid is in a rotating stirring mode in a light-driven fluid manipulation device according to an embodiment of the present invention; Figure 3 This is a diagram illustrating the driving mechanism of the LCE ring and the force analysis of the blade in a light-driven fluid manipulation device according to an embodiment of the present invention. Figure 4 This is a schematic diagram illustrating the working principle of a light-driven fluid manipulation device in linear propulsion mode according to an embodiment of the present invention. Figure 5 This is a schematic diagram illustrating the working principle of a light-driven fluid manipulation device in system rotation mode according to an embodiment of the present invention. Figure 6 This is a dimensionless simulation result of the spin and propulsion performance of the system under different photothermal powers in a light-driven fluid manipulation method according to an embodiment of the present invention. Figure 7 This is a dimensionless simulation result of the spin and propulsion performance of the system under different LCE ring radii in a light-driven fluid manipulation method according to an embodiment of the present invention. Figure 8 This is a schematic flowchart of a light-driven fluid manipulation method according to an embodiment of the present invention; Figure 9 This is a schematic diagram of the process of establishing a multi-field coupling model of light-heat-force-fluid in a light-driven fluid manipulation method according to an embodiment of the present invention.

[0017] Explanation of reference numerals in the attached figures: 1. Carrier platform; 2. LCE ring; 3. Propeller blade. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this application clearer, specific embodiments of this application are described clearly and completely below with reference to the accompanying drawings. It should be understood that the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments described in this application without creative effort will fall within the scope of protection of this application.

[0019] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the specification of this application is for the purpose of describing specific embodiments only and is not intended to limit this application; the terms "comprising," "including," "having," "containing," "comprise," etc., in the specification, claims, and accompanying drawings of this application are open-ended terms, indicating that a method comprises one or more steps, or an apparatus comprises one or more elements, but do not exclude the inclusion of other steps or elements. The terms "first," "second," etc., in the specification, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a specific order or primary / secondary relationship. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0020] In the description of this application, it should be understood that the terms "upper", "lower", "left", "right", "front", "rear", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0021] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0022] In this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0023] See Figures 1-5 ,in, Figure 3 (a) is a bar with an initial length of A schematic diagram of a straight liquid crystal elastomer rod bent into a ring under light. Figure 3(b) is a schematic diagram of the cross-section of LCE ring 2 when it is subjected to constant illumination; Figure 3 (c) is a schematic diagram of the driving torque generated by the non-uniform temperature distribution and non-uniform internal stress distribution inside LCE ring 2. Figure 3 (d) is a schematic diagram of the force analysis of the blade 3 moving in water. An embodiment of the present invention provides a light-driven fluid manipulation device, including: a carrier platform 1; an LCE ring 2 disposed on the carrier platform 1, the LCE ring 2 being made of a photothermal responsive liquid crystal elastomer material and configured to generate thermal deformation and form a self-rotation motion under steady-state illumination; and a blade 3 fixedly connected to the LCE ring 2, configured to rotate and drive the surrounding fluid to generate directional flow when the liquid crystal elastomer ring rotates under illumination.

[0024] In this embodiment, addressing the technical problems of existing fluid drive systems being highly dependent on external power supply, having complex and redundant electromechanical structures, and being difficult to achieve non-contact remote fluid control under special closed working conditions, the basic hardware architecture of this device includes a carrier platform 1 acting as a support base, an LCE ring 2 as the core energy conversion component, and a propeller 3 as the fluid work output component. The LCE ring 2 is made of a main-chain or side-chain photothermal responsive liquid crystal elastomer polymer material containing azobenzene or similar photoisomerization groups, and is suspended on the carrier platform 1 in a freely rotatable state by means of a central support shaft or limiting guide rail. The principle is that when a vertically downward steady-state light-emitting diode parallel beam is provided and irradiates the outer surface of the LCE ring 2, the polymer liquid crystal units on the light-receiving side absorb photon energy, generating a non-uniform local heating phenomenon. The internal lattice of the material undergoes a thermodynamic phase transition from a nematic phase to an isotropic phase, thereby inducing macroscopic thermal shrinkage deformation. Due to the asymmetry of this thermal shrinkage deformation on the ring topology, the LCE ring 2... The internal tangential stress difference generates a mechanical driving torque that causes the ring to continuously tumble and rotate around its geometric central axis. Simultaneously, the root end face of the blade 3 is fixedly connected to the outer wall of the LCE ring 2. When the LCE ring 2 begins to rotate smoothly under light-induced illumination, its mechanical torque is transmitted to the blade 3 without loss, driving the blade 3 to rotate synchronously in the fluid medium and push and shear the water using its water-facing surface. This overcomes the viscous damping force of the fluid and converts microscopic thermomechanical energy into macroscopic fluid kinetic energy, thereby generating a non-contact directional flow or stirring flow field. This structure directly eliminates the motor stator and rotor, transmission gear set and dynamic seal structure in traditional pump bodies. It is easy to process, and can be miniaturized and mass-produced at the chip level at low cost. It only requires external steady-state parallel light to continuously drive the fluid without connecting any physical wires, external power supply or electromagnetic controller, avoiding the risk of electrical short circuits and seal leakage. It is particularly suitable for special fluid control environments that are closed, sterile, toxic or difficult to wire, and its performance is better.

[0025] Optional, please refer to Figure 1 and Figure 2 The LCE ring 2 is formed by bending a straight liquid crystal elastomer rod into a ring and fixing it. The overall cross-section of the LCE ring 2 is a circular structure. The number of blades 3 is two or more, and they are distributed at equal distances along the circumference of the LCE ring 2.

[0026] In this embodiment, the LCE ring 2 is initially manufactured by extruding a liquid crystal elastomer into a slender straight rod with a specific aspect ratio. Subsequently, its two ends are precisely joined and bonded through a mechanical bending process to solidify it into a ring-shaped topological structure with initial closed-loop prestress. Furthermore, the overall cross-section of the straight rod and the final LCE ring 2 is strictly defined as a standard circular geometry. When a parallel beam of light irradiates from above in a unidirectional direction, the circular cross-section ensures a smooth and gradual transition in photon transmittance and thermal absorption profile on the radial scale. This effectively avoids the localized sharp focusing and accumulation of heat and stress abrupt distortion caused by the sharp corners of a square cross-section, thereby promoting a more continuous and uniform temperature gradient generated by the LCE ring 2 during its rotation cycle. The resulting spin angular velocity is smoother and more stable. At the same time, the number of blades 3 fixed on the LCE ring 2 is limited to two, three, or four blades, or more than two. When assembling, these blades 3 must be evenly distributed in a uniform array with equal angles along the outer circumference of the LCE ring 2, with the center of the ring as the reference point. This centrally symmetrical array distribution structure enables the hydrodynamic reaction resistance and the turbulent excitation force generated by each blade 3 when cutting into and discharging the fluid medium to cancel each other out at the center of the ring. This completely eliminates the radial runout of the shaft and the high-frequency resonance caused by uneven force on one side, so that the device can still maintain extremely high motion trajectory accuracy and microliter displacement consistency in viscous fluids.

[0027] Optional, please refer to Figure 1 and Figure 2 The blades 3 are configured to achieve multi-mode motion by changing their combined layout on the carrier platform 1. When the blades 3 are arranged symmetrically, the fluid is in a linear propulsion mode. When the blades 3 are arranged in an anti-symmetrical staggered manner, the fluid is in a rotating stirring mode.

[0028] This embodiment illustrates how to achieve multimodal operation of the same underlying hardware under different fluid conditions by changing the physical spatial topology of the blades 3. During actual assembly or application switching, the operator can adjust the relative spatial orientation of the blades 3 mounted on adjacent LCE rings 2 on the carrier platform 1 through preset micro-slots or plug-in interfaces. When performing fluid transport and pumping tasks within the microfluidic pipeline, the blades 3 on the left and right sides or multiple units are arranged in a symmetrical pattern with consistent rotation direction and parallel spatial geometry. At this time, the water flow thrust vector generated by the rotation of each blade 3 produces a positive superposition effect on the main axis, while the lateral induced slip flow is due to the... The spontaneous neutralization and cancellation of symmetry forces the controlled fluid to form a high-speed, pure straight-line propulsion water jet mode without yaw interference. Conversely, when rapid homogenization and mixing of biological reagents or dissolved oxygenation of environmental water bodies are required, the physical assembly posture of the blades 3 only needs to be manually changed to a reverse staggered or anti-symmetrical arrangement mode with opposite orientations or about the center point. At this time, the forces generated by adjacent drive units in the fluid interface water area are diametrically opposed, forming strong local shear friction and torsional torque, thereby generating a violent rotating stirring vortex field in the limited boundary chamber. The adjustability of this structural layout gives the single device a strong scene adaptability and multi-functional reuse value.

[0029] See Figure 8 The present invention also provides a control method for a light-driven fluid manipulation device, comprising the following steps: S1: Establish a multi-field coupling model of light-heat-force-fluid to determine the mapping relationship between light intensity parameters and fluid driving speed; S2: Perform non-contact control of fluid driving speed by remotely adjusting the light intensity acting on LCE ring 2.

[0030] In this embodiment, in step S1, the R&D control personnel pre-establish a multi-field coupled mathematical simulation model of light, heat, force, and flow within the computer terminal system, based on the thermodynamic properties of the material and the boundary conditions of fluid dynamics. This model covers the entire chain from photon energy absorption to fluid mechanical work. Using this pre-established analytical model, the control variable space is numerically scanned and solved simultaneously. This allows for precise calibration and characterization in the system database of the monotonic mapping function response curve between the light intensity power parameter (the sole input variable) and the macroscopic fluid linear drive velocity or vortex rotation angular velocity (the output dependent variable). When proceeding to step S2 for actual fluid manipulation, the operator or automated host computer only needs to follow the instructions of the microreactor. The required fluid displacement or flow rate can be found in the mapping curve. Then, the tunable LED light source array suspended in the ambient air outside the device is remotely adjusted by changing the digital signal of the current duty cycle. This instantly changes the absolute light radiation intensity that is actually vertically irradiated on the light-receiving surface of LCE ring 2. After receiving the light intensity change, the LCE ring 2 material body adjusts the degree of thermal contraction of its internal molecular chains at the millisecond level, thereby changing the output torque. This achieves stepless speed control of the water flow propulsion speed in the micro-nano channel without contact with any reaction liquid surface or laying any waterproof communication cables. This greatly improves the safety isolation and protection level for the manipulation of toxic and harmful experimental sample fluids, resulting in better performance.

[0031] Optional, see below Figure 9 The specific steps for establishing the optical-thermal-mechanical-fluid multi-field coupling model in S1 include: S11: Establish a spatial temperature field distribution model of the cross section of LCE ring 2 under steady-state illumination, considering photothermal input, thermal relaxation, and rotational effects, to obtain the temperature distribution law; S12: Based on the obtained temperature field distribution law, calculate thermal strain, elastic strain, and cross-sectional normal stress, integrate to obtain the driving torque around the axis, and clarify the relationship between the driving torque and photothermal power, contraction coefficient, and angular velocity; S13: Based on the driving torque generated by the above calculation, derive the equilibrium equations of blade 3 rotation, system rotation, and water flow propulsion, and perform dimensionless processing to improve the applicability and computational stability of the model.

[0032] In this embodiment, in stage S11, a partial differential prediction model of the steady-state temperature field distribution in the two-dimensional space inside the cylindrical cross-section grid of LCE ring 2 under specific illumination boundary conditions is first established using Newton's law of heat conduction and the theory of surface heat convection dissipation. The model fully considers comprehensive factors such as the heat generation rate of external equivalent light heating input, the inherent thermal relaxation time constant of the material, and the rotational effect of the phase difference of convective heat dissipation caused by rotation, and accurately solves the distribution law of the eccentric temperature gradient cloud map formed between the illuminated surface and the backlit surface inside the cross-section due to the difference in heat accumulation.

[0033] Upon entering stage S12, the non-uniform temperature field node data obtained above is used as the input load. Combining the thermal expansion and contraction coefficient and the basic parameter curve of the nonlinear hyperelastic modulus of the elastic material, the microscopic thermal strain and macroscopic elastic distortion displacement of the internal grid caused by the temperature difference are derived and calculated based on Hooke's law in solid mechanics. Furthermore, the unbalanced normal stress vector distributed throughout the entire stressed section is subjected to calculus mathematical operations to obtain the analytical expression of the effective driving rotational torque that drives the ring body to roll around the longitudinal geometric axis.

[0034] Finally, in stage S13, the fluid dynamics calculation branch is entered. The derived core driving torque is used as the active power source. At the same time, the surrounding medium laminar viscous damping parameters related to the Reynolds number are introduced. Based on the d'Alembert principle of rigid body dynamics, a set of dynamic equilibrium differential equations is established to counteract the angular acceleration generated by the forced rotation of blade 3 and the water flow recoil resistance torque. In order to eliminate the interference of different physical unit dimensions on the stability of matrix operations, dimensionless normalization and dimensionality reduction processing is performed on each term of the complex equation set by dividing by the reference value. This significantly reduces the probability of singular matrix error when calculating nonlinear high-order models and significantly improves the model's universal applicability in the design and evaluation of microelectromechanical systems of different sizes.

[0035] Optional, see below Figure 2 and Figure 3 The temperature field distribution model of the LCE ring 2 cross section under steady-state illumination in S11 is obtained by solving the energy conservation equation, which is as follows: ; in, This represents the coordinates of any point on the cross-section of LCE ring 2. Radial coordinates, Let R be the circumferential angle, and R represent the radius of LCE ring 2. This represents the characteristic thermal relaxation time of the cross section of LCE ring 2. Indicates the rotational angular velocity. Indicates the equivalent photothermal rate. This represents the uniform offset of the temperature field.

[0036] In this embodiment, the detailed derivation of the energy conservation partial differential equation is as follows: Let the perimeter of LCE ring 2 be... The radius of LCE ring 2 is R, and the radius of the LCE rod cross section is... Under steady-state parallel illumination, LCE ring 2 absorbs light energy and produces a non-uniform temperature distribution; the coordinates of any point on the cross-section of the LCE rod are in polar coordinates. To indicate, radial coordinates , Circumferential angle; cross-sectional temperature field The calculation formula is: (1) in This represents the uniform offset of the temperature field. This represents the amplitude in a temperature field distributed using a cosine function. This represents the amplitude in a temperature field with a sinusoidal function distribution; for the steady-state rotation of LCE ring 2, and Can be written as: (2) (3) This represents the characteristic thermal relaxation time of the cross section of LCE ring 2. It is the rotational angular velocity. This is the equivalent photothermal rate; therefore, the temperature field can be written as: (4); The equation includes a characteristic thermal relaxation time decay term, which is determined by the thermal conductivity of the material itself and characterizes the rate at which the system dissipates heat to the ambient cold source, and an equivalent photothermal heating rate gain term, which represents the rate at which an external parallel LED light source is projected into the material and absorbed by the molecular lattice and converted into internal energy. By using the finite difference method to perform multi-step iterative optimization calculations on this transient partial differential equation in a mathematical solver, the analytical solution of the precise quantitative distribution function of the temperature field inside the cross section along the polar radius and polar angle directions after the system enters the thermal equilibrium steady state stage can be obtained.

[0037] Optional, see below Figure 2 and Figure 3 Thermal strain in S12 Elastic strain and the normal stress on section 2 of LCE ring The calculation equation is as follows: ; ; ; in Indicates the shrinkage coefficient. Indicates the elastic modulus. This represents the average axial strain. This represents static strain.

[0038] In this embodiment, the normal stress on the cross section of LCE ring 2 The specific derivation of the calculation equation is as follows: For ease of calculation, assume thermal strain caused by uniform axial contraction. With temperature field The relationship is linear. Therefore, thermal strain Can be written as: (5) Elastic strain on the cross-section of LCE ring 2 during stable rotation From mean axial strain Static strain and dynamic strain Composition; therefore, the elastic strain of the cross section of LCE ring 2 It can be calculated as: (6) The static strain is determined by the bending curvature of the ring, i.e. (7) (8) in, This represents the average axial strain. The length after deformation is given, based on the fact that axial strain is negligible relative to thermal strain, and the average temperature of the cross section of LCE ring 2 under steady-state rotation conditions. Since it has no effect on the generation of dynamic strain, by combining formulas (1), (4), and (7), formula (6) can be rewritten as: (9) Assuming the material of LCE ring 2 is a linear elastic body, according to Hooke's law, the normal stress on the ring section is... This can be further expressed as: (10).

[0039] Optional, see below Figure 2 and Figure 3 In S12, LCE ring 2 is wound The calculation equations for the driving torque of the shaft and the driving torque of LCE ring 2 itself are as follows: ; ; in, This represents the radius of the LCE rod's cross-section. This is expressed as the area of ​​each tiny unit in the polar coordinate system of the LCE ring 2 cross section. Stress on the surface.

[0040] In this embodiment, the calculation equations for the driving torque of LCE ring 2 around the axis and the driving torque of LCE ring 2 itself are derived as follows: Among them, the calculation of LCE ring 2 around Shaft drive torque It can be represented as: (11) Then the driving torque of LCE ring 2 is Combining formulas (9), (10), and (11), the driving torque of LCE ring 2 is obtained. Rewritten as: (12).

[0041] Optional, see below Figure 2 and Figure 3 The specific balance equations for the rotation of blade 3, system rotation, and water propulsion in S13 are as follows: The equation for the angular velocity of the blade is: ; The system's rotational angular velocity equation is: ; The equation for water propulsion velocity is: ; in, Let be the rotational damping coefficient of blade 3. The length of blade 3, The forward damping coefficient is... Let be the system rotational damping coefficient. The lever arm is the distance between the two blades.

[0042] In this embodiment, when the blades rotate, the driving force of the water on the blades 3 It is proportional to the velocity of blade 3 relative to still water: (13) In the formula Let be the rotational damping coefficient of blade 3. The rotational angular velocity of blade 3 (under steady rotation) ), The blade length is 3. For propulsion speed. Assume forward damping coefficient. The water resistance is proportional to the self-propulsion speed of carrier platform 1. It can be represented as: (14) When the system rotates as a whole, the drag torque and the rotational angular velocity The relationship is: (15) in The lever arm between the two blades. Let be the rotational damping coefficient of the system; in self-propelled mode, the driving torque is balanced by the water's drag torque. (16) Meanwhile, the force balance in the propulsion direction can be expressed as: (17) Formulas (13)-(17) constitute a complete set of equilibrium equations describing the translation and overall rotation of the system; According to formulas (13)-(17), the angular velocity of the blade is given as follows: (18); The system's rotational angular velocity is: (19); The propulsion speed of the water flow is: (20).

[0043] Optional, see below Figure 2 and Figure 3 The specific calculation formula after dimensionless processing in S13 is as follows: The temperature field is dimensionless. ; The driving torque is dimensionless. ; The dimensionless angular velocity of the propeller blades is reduced to... ; The system rotational speed is dimensionless. ; The propulsion speed is dimensionless. .

[0044] In this embodiment, the steady-state temperature field, driving torque, rotational angular velocity, propulsion speed, and system rotational speed are dimensionless. To simplify the analysis process, reduce calculation errors, and improve model stability, all parameters are normalized as follows: , , , , , , , , , , , , Ambient temperature; In formula (4), the temperature field is dimensionless as follows: ; Formula (12) has a dimensionless driving torque. ; Formula (18) gives the dimensionless angular velocity of the blade as follows: ; Formula (19) gives the system rotational velocity dimensionless as follows: ; Formula (20) reduces the propulsion velocity to a dimensionless value. .

[0045] In the specific implementation process, in order to verify and solve the above-established light-heat-force-fluid multi-field coupling model, the coupling equations involving temperature field, driving torque, blade 3-angular velocity, water flow propulsion speed and system rotation speed are transformed into explicit analytical equations containing only a few dimensionless parameters. Based on the above derivation process, scientific computing software such as MATLAB is used for numerical solution and simulation analysis.

[0046] In one embodiment of the present invention, reference is made to Figure 6 As shown, where, Figure 6 (a) is a graph showing the relationship between driving torque and blade angular velocity under different photothermal powers; Figure 6 (b) is a graph showing the change of blade angular velocity with photothermal power; Figure 6 (c) is a graph showing the change in water flow propulsion speed with photothermal power; Figure 6 (d) is a graph showing the relationship between driving torque and blade angular velocity under different photothermal powers. The system performance is significantly affected by the photothermal input power. As the photothermal power increases, the rotational angular velocity of blade 3, the water flow propulsion speed of the system, and the overall system rotation speed all show a significant upward trend. The underlying physical mechanism for this phenomenon is that the higher the photothermal power, the more light energy LCE ring 2 absorbs per unit time, the greater the temperature gradient established in its cross-section and the greater the thermally induced contraction deformation, thus generating a stronger driving torque, which in turn increases the speed of various motions of the system. In addition, the relationship between the driving torque and angular velocity of LCE ring 2 under different photothermal powers shows that, at the same rotational angular velocity, the greater the photothermal power, the greater the driving torque output by the system. However, as the angular velocity gradually increases, the driving torque shows a gradual decreasing trend. This is because the increase in photothermal power can directly enhance the photothermal mechanical conversion effect and thus increase the driving torque. However, an excessive increase in angular velocity will cause LCE ring 2 to be heated more uniformly during the rotation cycle, weakening the eccentric temperature gradient, reducing the thermally induced deformation, and ultimately leading to a corresponding decrease in the output driving torque.

[0047] In another embodiment of the present invention, reference is made to Figure 7 As shown, where, Figure 7 (a) is a graph showing the relationship between driving torque and blade angular velocity under different LCE ring 2 radii; Figure 7 (b) is a graph showing the change of blade angular velocity with the radius of LCE ring 2; Figure 7 (c) is a graph showing the water propulsion velocity as a function of the radius of LCE ring 2; Figure 7(d) shows the relationship between driving torque and blade angular velocity under different ring radii. While keeping other system parameters set to fixed baseline values, the geometric radius of LCE ring 2 was examined. The impact on system drive performance is as follows, where the remaining system parameters are set as follows: , , , , , , As the radius of LCE ring 2 gradually increases, the system's spin angular velocity, water flow propulsion speed, and overall system rotation speed all show a decreasing trend, and eventually tend to stabilize after the radius increases to a certain extent. At the same time, the curves showing the change of driving torque under different LCE ring 2 radii also indicate that as the radius of LCE ring 2 increases, the overall driving torque output by the system shows a decreasing trend. This provides reliable theoretical data support for the size selection and miniaturization design of LCE ring 2 in practical applications.

[0048] Through the above specific implementation methods and simulation verification analysis, it can be clearly concluded that the light-driven fluid manipulation device provided in this embodiment has significant technical advantages and beneficial effects. First, the device achieves completely non-contact actuation, requiring only steady-state parallel light illumination to continuously drive the fluid, completely eliminating the constraints of any external power supply, wires, or electrical controllers, making it particularly suitable for special working environments such as closed, sterile, toxic, or difficult-to-wire environments. Second, the device achieves extreme simplification of its structure, with the core power drive components being only the LCE ring 2 and the matching blades 3, eliminating the need for traditional motors, transmission gears, and dynamic sealing structures, greatly reducing manufacturing difficulty and facilitating system miniaturization and low cost. Batch processing; secondly, the system possesses extremely high precision and controllability. Based on the established light-heat-force-fluid theoretical calculation model, operators can precisely control the fluid driving speed and driving torque by adjusting the external light intensity, the geometric parameters of LCE ring 2 (such as ring radius and cross-sectional radius), or the blade parameters; finally, the device has multi-mode motion capability. By flexibly changing the physical assembly layout of the blades, such as adopting a symmetrical or anti-symmetrical staggered arrangement, a single device can freely switch between various fluid control modes, such as linear directional propulsion pumping or in-situ rotary vortex stirring. It is widely applicable to cutting-edge technology scenarios such as microfluidic chip mixing, fluid pumping, and in-situ water purification.

[0049] While the present invention has been disclosed above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and all such changes and modifications will fall within the scope of protection of the present invention.

Claims

1. A light-driven fluid manipulation device, characterized in that, include: Carrier platform (1); The LCE ring (2) disposed on the carrier platform (1) is made of photothermal responsive liquid crystal elastomer material and is configured to generate thermal deformation and form a self-rotating motion under steady-state illumination. The blade (3) fixedly connected to the LCE ring (2) is configured such that when the LCE ring (2) rotates under illumination, the blade (3) rotates accordingly and drives the surrounding fluid to generate directional flow. The LCE ring (2) is formed by bending a straight rod of liquid crystal elastomer into a ring and fixing it. The overall cross-section of the LCE ring (2) is a circular structure. The number of blades (3) is two or more, and they are distributed at equal distances along the circumference of the LCE ring (2). The blades (3) are configured to achieve multi-mode motion by changing their combined layout on the carrier platform (1). When the blades (3) are arranged symmetrically, the fluid is in a straight-line propulsion mode. When the blades (3) are arranged in an anti-symmetrical staggered manner, the fluid is in a rotating stirring mode.

2. A control method for the light-driven fluid manipulation device as described in claim 1, characterized in that, Includes the following steps: S1: Establish a multi-field coupled model of light-heat-force-fluid to determine the mapping relationship between light intensity parameters and fluid driving velocity; S2: The fluid drive speed is controlled non-contactly by remotely adjusting the light intensity acting on the LCE ring (2); The specific steps for establishing the optical-thermal-mechanical-fluid multi-field coupling model in S1 include: S11: Establish a spatial temperature field distribution model of the LCE ring (2) cross section under steady-state illumination, considering photothermal input, thermal relaxation and rotation effects, and obtain the temperature field distribution law; S12: Based on the obtained temperature field distribution law, calculate the thermal strain, elastic strain, and cross-sectional normal stress, and integrate to obtain the stress around the cross-section. The driving torque of the shaft is determined, and the relationship between the driving torque and the photothermal power, the coefficient of contraction, and the angular velocity is clarified. S13: Based on the driving torque generated by the aforementioned calculation, the balance equations of blade (3) rotation, system rotation and water flow propulsion are derived and dimensionless processing is performed to improve the applicability and calculation stability of the model; The LCE ring (2) in S12 is wound The calculation equations for the driving torque of the shaft and the driving torque of the LCE ring (2) itself are as follows: ； ； in, The radius of the cross-section of the liquid crystal elastomer rod. This is expressed as the area of ​​each tiny unit in the polar coordinate system of the LCE ring (2) cross section. Stress on; The specific balance equations for the rotation of the blade (3), the rotation of the system, and the propulsion of the water flow in S13 are as follows: The equation for the angular velocity of the propeller blade (3) is: ; The system's rotational angular velocity equation is: ; The equation for water propulsion velocity is: ; in, Let be the rotational damping coefficient of the blade (3). The length of the blade (3) is... The forward damping coefficient is... Let be the system rotational damping coefficient. The lever arm is the distance between the two blades.

3. The control method for the light-driven fluid manipulation device according to claim 2, characterized in that, The spatial temperature field distribution model of the LCE ring (2) cross section under steady-state illumination in S11 is obtained by solving the energy conservation equation, which is as follows: ； in, Indicate the coordinates of any point on the cross section of the LCE ring (2). Radial coordinates, Let R be the circumferential angle, and let R be the radius of the LCE ring (2). This represents the characteristic thermal relaxation time of the cross section of the LCE ring (2). Indicates the rotational angular velocity. Indicates the equivalent photothermal rate. This represents the uniform offset of the temperature field.

4. The control method of the light-driven fluid manipulation device according to claim 3, characterized in that, thermal strain in S12 Elastic strain and the normal stress on the LCE ring (2) section The calculation equation is as follows: ； ； ； in Indicates the shrinkage coefficient. Indicates the elastic modulus. This represents the average axial strain. This represents static strain.

5. The control method for the light-driven fluid manipulation device according to claim 4, characterized in that, The specific calculation formula after dimensionless processing in S13 is as follows: The temperature field is dimensionless. ; The driving torque is dimensionless. ; The dimensionless angular velocity of the propeller (3) is converted to ; The system rotational speed is dimensionless. ; The propulsion speed is dimensionless. ; in, , , , , , , , , , , , , The ambient temperature.

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