基于4D打印技术的液晶弹性体软体驱动器设计与制备

       液晶弹性体（Liquid Crystal Elastomers，LCEs）是一类兼具了液晶有序性以及聚合物网络软弹性的新型智能材料，因其大幅值、各向异性的可逆驱动能力受到了广泛的关注。基于4D打印技术的LCEs软体驱动器具有驱动系统简单、设计自由度大以及集成化程度高等显著优势，在生物医疗、航空航天、智能机器人等领域具有巨大的应用潜力。然而目前LCEs软体驱动器存在需要持续性的外部激励以维持其驱动形态、驱动形态单一难以调制、难以执行高负载任务以及激励环境复杂等问题。因此本课题对LCEs软体驱动器的形态控制策略以及材料设计方法展开研究，提出了通过控制冷却速率实现驱动形态锁定与调制的策略，以及制备LCEs纤维增强聚合物复合材料的方法，有效地提升了其可控能力、驱动能力与机械性能。

       LCEs软体驱动器的预编程设计与制备是本研究开展的前提。基于LCEs各向异性驱动机制，本课题建立了等效有限元仿真预测模型，有效指导了工艺参数及打印路径的选取与设计。结合仿真结果，本课题利用自主研发的墨水直写打印设备对LCEs介晶单元进行取向编程，实现了LCEs软体驱动器的预编程设计与制备。针对LCEs软体驱动器需要持续性外部激励以维持其驱动形态以及驱动形态单一难以调制的问题，本课题基于介晶单元相变延迟的原理，提出了通过控制冷却速率实现驱动形态锁定与调制的方法，实现了LCEs软体驱动器在室温条件下的形态锁定以及多模态获取。本研究通过多模态仿生花朵结构以及自适应智能软体抓手的应用说明该控制策略有效地提升了驱动器的可控能力。此外，针对LCEs软体驱动器难以执行高负载任务以及激励环境复杂的问题，本课题基于纤维增强聚合物复合材料良好的机械性能与电热效应，设计了一种LCEs纤维增强聚合物复合材料，实现了高性能LCEs软体驱动器的制备。本研究通过高负载电控抓手的应用展示了基于该设计方法的驱动器良好的驱动能力与机械性能。

       综上所述，本研究课题为LCEs软体驱动器提供了有效的设计、制备、控制与优化方法，显著提升了其可控能力、驱动能力与机械性能，具有重要的研究意义与工程价值。

[1] LI T, LI G, LIANG Y, et al. Review of materials and structures in soft obotics[J/OL]. Chinese Journal of Theoretical and Applied Mechanics, 2016, 48(4): 756-766.
[2] WHITESIDES G M. Soft Robotics[J/OL]. Angewandte Chemie International Edition, 2018, 57(16): 4258-4273.
[3] SCHAFFNER M, FABER J A, PIANEGONDA L, et al. 3D printing of robotic soft actuators with programmable bioinspired architectures[J/OL]. Nature Communications 2018 9:1, 2018, 9(1): 1-9.
[4] ZAIDI S, MASELLI M, LASCHI C, et al. Actuation Technologies for Soft Robot Grippers and Manipulators: A Review[J/OL]. Current Robotics Reports 2021 2:3, 2021, 2(3): 355-369.
[5] NGO T D, KASHANI A, IMBALZANO G, et al. Additive manufacturing (3D printing): A review of materials, methods, applications and challenges[J/OL]. Composites Part B: Engineering, 2018, 143: 172-196.
[6] XU X, ROBLES-MARTINEZ P, MADLA C M, et al. Stereolithography (SLA) 3D printing of an antihypertensive polyprintlet: Case study of an unexpected photopolymer-drug reaction[J/OL]. Additive Manufacturing, 2020, 33: 101071.
[7] SHAHZAD A, LAZOGLU I. Direct ink writing (DIW) of structural and functional ceramics: Recent achievements and future challenges[J/OL]. Composites Part B: Engineering, 2021, 225: 109249.
[8] OLIVEIRA J P, LALONDE A D, MA J. Processing parameters in laser powder bed fusion metal additive manufacturing[J/OL]. Materials & Design, 2020, 193: 108762.
[9] GOH G D, YAP Y L, AGARWALA S, et al. Recent Progress in Additive Manufacturing of Fiber Reinforced Polymer Composite[J/OL]. Advanced Materials Technologies, 2019, 4(1): 1800271.
[10] MOMENI F, M.MEHDI HASSANI.N S, LIU X, et al. A review of 4D printing[J/OL]. Materials and Design, 2017, 122: 42-79.
[11] GE Q, SAKHAEI A H, LEE H, et al. Multimaterial 4D Printing with Tailorable Shape Memory Polymers[J/OL]. Scientific Reports 2016 6:1, 2016, 6(1): 1-11.
[12] KUANG X, ROACH D J, WU J, et al. Advances in 4D Printing: Materials and Applications[J/OL]. Advanced Functional Materials, 2019, 29(2): 1-23.
[13] GENNES P De, PROST J. The physics of liquid crystals[J/OL]. Book in Physics Today, 1993. 10. 12808028.
[14] GUO G, WU Q, LIU F, et al. Solvent-Cast-Assisted Printing of Biomimetic Morphing Hydrogel Structures with Solvent Evaporation-Induced Swelling Mismatch[J/OL]. Advanced Functional Materials, 2022, 32(2): 2108548.
[15] ZHAO Q, QI H J, XIE T. Recent progress in shape memory polymer: New behavior, enabling materials, and mechanistic understanding[J/OL]. Progress in Polymer Science, 2015, 49-50: 79-120.
[16] WANG Z, TIAN H, HE Q, et al. Reprogrammable, Reprocessible, and Self-Healable Liquid Crystal Elastomer with Exchangeable Disulfide Bonds[J/OL]. ACS Applied Materials and Interfaces, 2017, 9(38): 33119-33128.
[17] UBE T, KAWASAKI K, IKEDA T. Photomobile Liquid-Crystalline Elastomers with Rearrangeable Networks[J/OL]. Advanced Materials, 2016, 28(37): 8212-8217.
[18] PEI Z, YANG Y, CHEN Q, et al. Mouldable liquid-crystalline elastomer actuators with exchangeable covalent bonds[J/OL]. Nature Materials 2013 13:1, 2013, 13(1): 36-41.
[19] CHEN M, GAO M, BAI L, et al. Recent Advances in 4D Printing of Liquid Crystal Elastomers[J/OL]. Advanced Materials, 2023, 35(23): 2209566.
[20] GRAY G W, HARRISON K J, NASH J A. New family of imematic liquid crystals for displays[J/OL]. Electronics Letters, 1973, 9(6): 130-131.
[21] SHEN W, DU B, LIU J, et al. A facile approach for the preparation of liquid crystalline polyurethane for light-responsive actuator films with self-healing performance[J/OL]. Materials Chemistry Frontiers, 2021, 5(7): 3192-3200.
[22] GUIN T, SETTLE M J, KOWALSKI B A, et al. Layered liquid crystal elastomer actuators[J/OL]. Nature Communications 2018 9:1, 2018, 9(1): 1-7.
[23] CHEN L, BISOYI H K, HUANG Y, et al. Healable and Rearrangeable Networks of Liquid Crystal Elastomers Enabled by Diselenide Bonds[J/OL]. Angewandte Chemie International Edition, 2021, 60(30): 16394-16398.
[24] YIN L, MIAO T F, CHENG X X, et al. Chiral Liquid Crystalline Elastomer for Twisting Motion without Preset Alignment of Mesogens[J/OL]. ACS Macro Letters, 2021, 10(6): 690-696.
[25] BRÖMMEL F, KRAMER D, FINKELMANN H. Preparation of Liquid Crystalline Elastomers[J/OL]. Adv Polym Sci, 2012, 250: 1-48.
[26] WANG Y, LIU J, YANG S. Multi-functional liquid crystal elastomer composites[J/OL]. Applied Physics Reviews, 2022, 9(1): 011301.
[27] WU J, YAO S, ZHANG H, et al. Liquid Crystal Elastomer Metamaterials with Giant Biaxial Thermal Shrinkage for Enhancing Skin Regeneration[J/OL]. Advanced Materials, 2021, 33(45): 2106175.
[28] MOL G N, HARRIS K D, BASTIAANSEN C W M, et al. Thermo-Mechanical Responses of Liquid-Crystal Networks with a Splayed Molecular Organization[J/OL]. Advanced Functional Materials, 2005, 15(7): 1155-1159.
[29] WU Y, ZHANG S, YANG Y, et al. Locally controllable magnetic soft actuators with reprogrammable contraction-derived motions[J/OL]. Science Advances, 2022, 8(25): 6021.
[30] ZHANG J, GUO Y, HU W, et al. Liquid Crystal Elastomer-Based Magnetic Composite Films for Reconfigurable Shape-Morphing Soft Miniature Machines[J/OL]. Advanced Materials, 2021, 33(8): 2006191.
[31] PALAGI S, MARK A G, REIGH S Y, et al. Structured light enables biomimetic swimming and versatile locomotion of photoresponsive soft microrobots[J/OL]. Nature Materials 2016 15:6, 2016, 15(6): 647-653.
[32] WANG Z, LI K, HE Q, et al. A Light-Powered Ultralight Tensegrity Robot with High Deformability and Load Capacity[J/OL]. Advanced Materials, 2019, 31(7): 1806849.
[33] DE HAAN L T, VERJANS J M N, BROER D J, et al. Humidity-responsive liquid crystalline polymer actuators with an asymmetry in the molecular trigger that bend, fold, and curl[J/OL]. Journal of the American Chemical Society, 2014, 136(30): 10585-10588.
[34] STUMPEL J E, WOUTERS C, HERZER N, et al. An Optical Sensor for Volatile Amines Based on an Inkjet-Printed, Hydrogen-Bonded, Cholesteric Liquid Crystalline Film[J/OL]. Advanced Optical Materials, 2014, 2(5): 459-464.
[35] YAKACKI C M, SAED M, NAIR D P, et al. Tailorable and programmable liquid-crystalline elastomers using a two-stage thiol–acrylate reaction[J/OL]. RSC Advances, 2015, 5(25): 18997-19001.
[36] KUMAR S, KIM J H, SHI Y. What Aligns Liquid Crystals on Solid Substrates? The Role of Surface Roughness Anisotropy[J/OL]. Physical Review Letters, 2005, 94(7): 077803.
[37] BRANNUM M T, STEELE A M, VENETOS M C, et al. Light Control with Liquid Crystalline Elastomers[J/OL]. Advanced Optical Materials, 2019, 7(6): 1801683.
[38] TAN L J, ZHU W, ZHOU K. Recent Progress on Polymer Materials for Additive Manufacturing[J/OL]. Advanced Functional Materials, 2020, 30(43): 2003062.
[39] CHEN J, LIU X, TIAN Y, et al. 3D-Printed Anisotropic Polymer Materials for Functional Applications[J/OL]. Advanced Materials, 2022, 34(5): 2102877.
[40] MA S, LI X, HUANG S, et al. A Light-Activated Polymer Composite Enables On-Demand Photocontrolled Motion: Transportation at the Liquid/Air Interface[J/OL]. Angewandte Chemie, 2019, 131(9): 2681-2685.
[41] VAN OOSTEN C L, BASTIAANSEN C W M, BROER D J. Printed artificial cilia from liquid-crystal network actuators modularly driven by light[J/OL]. Nature Materials 2009 8:8, 2009, 8(8): 677-682.
[42] POTEKHINA A, WANG C. Numerical simulation and experimental validation of bending and curling behaviors of liquid crystal elastomer beams under thermal actuation[J/OL]. Applied Physics Letters, 2021, 118(24): 241903.
[43] IAMSAARD S, ASSHOFF S J, MATT B, et al. Conversion of light into macroscopic helical motion[J/OL]. Nature Chemistry 2014 6:3, 2014, 6(3): 229-235.
[44] WIE J J, SHANKAR M R, WHITE T J. Photomotility of polymers[J/OL]. Nature Communications 2016 7:1, 2016, 7(1): 1-8.
[45] NOCENTINI S, MARTELLA D, WIERSMA D S, et al. Beam steering by liquid crystal elastomer fibres[J/OL]. Soft Matter, 2017, 13(45): 8590-8596.
[46] LEE K M, BUNNING T J, WHITE T J. Autonomous, Hands-Free Shape Memory in Glassy, Liquid Crystalline Polymer Networks[J/OL]. Advanced Materials, 2012, 24(21): 2839-2843.
[47] KUMAR K, KNIE C, BLÉGER D, et al. A chaotic self-oscillating sunlight-driven polymer actuator[J/OL]. Nature Communications 2016 7:1, 2016, 7(1): 1-8.
[48] AHN S K, WARE T H, LEE K M, et al. Photoinduced Topographical Feature Development in Blueprinted Azobenzene-Functionalized Liquid Crystalline Elastomers[J/OL]. Advanced Functional Materials, 2016, 26(32): 5819-5826.
[49] SAADI M A S R, MAGUIRE A, POTTACKAL N T, et al. Direct Ink Writing: A 3D Printing Technology for Diverse Materials[J/OL]. Advanced Materials, 2022, 34(28): 2108855.
[50] LIGON S C, LISKA R, STAMPFL J, et al. Polymers for 3D Printing and Customized Additive Manufacturing[J/OL]. Chemical Reviews, 2017, 117(15): 10212-10290.
[51] GANTENBEIN S, MASANIA K, WOIGK W, et al. Three-dimensional printing of hierarchical liquid-crystal-polymer structures[J/OL]. Nature 2018 561:7722, 2018, 561(7722): 226-230.
[52] HERBERT K M, FOWLER H E, MCCRACKEN J M, et al. Synthesis and alignment of liquid crystalline elastomers[J/OL]. Nature Reviews Materials 2021 7:1, 2021, 7(1): 23-38.
[53] WAN X, LUO L, LIU Y, et al. Direct Ink Writing Based 4D Printing of Materials and Their Applications[J/OL]. Advanced Science, 2020, 7(16): 1-29.
[54] WANG Z, WANG Z, ZHENG Y, et al. Three-dimensional printing of functionally graded liquid crystal elastomer[J/OL]. Science Advances, 2020, 6(39) : eabc0034.
[55] ZHANG C, LU X, FEI G, et al. 4D Printing of a Liquid Crystal Elastomer with a Controllable Orientation Gradient[J/OL]. ACS Applied Materials and Interfaces, 2019, 11(47): 44774-44782.
[56] PENG X, WU S, SUN X, et al. 4D Printing of Freestanding Liquid Crystal Elastomers via Hybrid Additive Manufacturing[J/OL]. Advanced Materials, 2022, 34(39): 2204890.
[57] MA J, YANG Y, VALENZUELA C, et al. Mechanochromic, Shape-Programmable and Self-Healable Cholesteric Liquid Crystal Elastomers Enabled by Dynamic Covalent Boronic Ester Bonds[J/OL]. Angewandte Chemie International Edition, 2022, 61(9): e202116219.
[58] KOTIKIAN A, MCMAHAN C, DAVIDSON E C, et al. Untethered soft robotic matter with passive control of shape morphing and propulsion. Science Robotics, 2019: 7044
[2023-01-20].
[59] ZHAI F, FENG Y, LI Z, et al. 4D-printed untethered self-propelling soft robot with tactile perception: Rolling, racing, and exploring[J/OL]. Matter, 2021, 4(10): 3313-3326.
[60] DAVIDSON E C, KOTIKIAN A, LI S, et al. 3D Printable and Reconfigurable Liquid Crystal Elastomers with Light-Induced Shape Memory via Dynamic Bond Exchange[J/OL]. Advanced Materials, 2020, 32(1): 1905682.
[61] CHEN G, JIN B, SHI Y, et al. Rapidly and Repeatedly Reprogrammable Liquid Crystalline Elastomer via a Shape Memory Mechanism[J/OL]. Advanced Materials, 2022, 34(21): 2201679.
[62] ROACH D J, SUN X, PENG X, et al. 4D Printed Multifunctional Composites with Cooling-Rate Mediated Tunable Shape Morphing[J/OL]. Advanced Functional Materials, 2022, 32(36): 2203236.
[63] LIU H, TIAN H, LI X, et al. Shape-programmable, deformation-locking, and self-sensing artificial muscle based on liquid crystal elastomer and low–melting point alloy[J/OL]. Science Advances, 2022, 8(20): 5722.
[64] KIM H, AH LEE J, AMBULO C P, et al. Intelligently Actuating Liquid Crystal Elastomer-Carbon Nanotube Composites[J/OL]. Advanced Functional Materials, 2019, 29(48): 1905063.
[65] FORD M J, AMBULO C P, KENT T A, et al. A multifunctional shape-morphing elastomer with liquid metal inclusions[J/OL]. Proceedings of the National Academy of Sciences, 2019, 116(43): 21438-21444.
[66] DITTER D, BLÜMLER P, KLÖCKNER B, et al. Microfluidic Synthesis of Liquid Crystalline Elastomer Particle Transport Systems which Can Be Remote-Controlled Magnetically[J/OL]. Advanced Functional Materials, 2019, 29(29): 1902454.
[67] WANG Y, DANG A, ZHANG Z, et al. Repeatable and Reprogrammable Shape Morphing from Photoresponsive Gold Nanorod/Liquid Crystal Elastomers[J/OL]. Advanced Materials, 2020, 32(46): 2004270.
[68] KOHLMEYER R R, CHEN J. Wavelength-Selective, IR Light-Driven Hinges Based on Liquid Crystalline Elastomer Composites[J/OL]. Angewandte Chemie, 2013, 125(35): 9404-9407.
[69] WANG M, CHENG Z W, ZUO B, et al. Liquid Crystal Elastomer Electric Locomotives[J/OL]. ACS Macro Letters, 2020, 9(6): 860-865.
[70] LIU J, GAO Y, WANG H, et al. Shaping and Locomotion of Soft Robots Using Filament Actuators Made from Liquid Crystal Elastomer–Carbon Nanotube Composites[J/OL]. Advanced Intelligent Systems, 2020, 2(6): 1900163.
[71] AMBULO C P, FORD M J, SEARLES K, et al. 4D-Printable Liquid Metal-Liquid Crystal Elastomer Composites.[J/OL]. ACS applied materials & interfaces, 2021, 13(11): 12805-12813.
[72] WENG S, KUANG X, ZHANG Q, et al. 4D Printing of Glass Fiber-Regulated Shape Shifting Structures with High Stiffness[M/OL]//ACS Applied Materials and Interfaces. American Chemical Society, 2021: 12797-12804.
[73] YU Y, LIU H, QIAN K, et al. Material characterization and precise finite element analysis of fiber reinforced thermoplastic composites for 4D printing [J/OL]. Computer-Aided Design, 2020, 122: 102817.
[74] YU Y, QIAN K, YANG H, et al. Hybrid IGA-FEA of fiber reinforced thermoplastic composites for forward design of AI-enabled 4D printing[J/OL]. Journal of Materials Processing Technology, 2022, 302: 117497.
[75] WANG Q, TIAN X, ZHANG D, et al. Programmable spatial deformation by controllable off-center freestanding 4D printing of continuous fiber reinforced liquid crystal elastomer composites[J/OL]. Nature Communications 2023 14:1, 2023, 14(1): 1-11.
[76] ZENG C, LIU L, BIAN W, et al. 4D printed electro-induced continuous carbon fiber reinforced shape memory polymer composites with excellent bending resistance[J/OL]. Composites Part B: Engineering, 2020, 194: 108034.
[77] PYO Y, KANG M, JANG J young, et al. Design of a shape memory composite(SMC) using 4D printing technology[J/OL]. Sensors and Actuators, A: Physical, 2018, 283: 187-195.
[78] DONG K, PANAHI-SARMAD M, CUI Z, et al. Electro-induced shape memory effect of 4D printed auxetic composite using PLA/TPU/CNT filament embedded synergistically with continuous carbon fiber: A theoretical & experimental analysis[J/OL]. Composites Part B: Engineering, 2021, 220: 108994.
[79] WANG Q, TIAN X, HUANG L, et al. Programmable morphing composites with embedded continuous fibers by 4D printing[J/OL]. Materials and Design, 2018, 155: 404-413.
[80] ZHANG B, LI H, CHENG J, et al. Mechanically Robust and UV-Curable Shape-Memory Polymers for Digital Light Processing Based 4D Printing[J/OL]. Advanced Materials, 2021, 33(27): 2101298.
[81] LE DUIGOU A, FRULEUX T, MATSUZAKI R, et al. 4D printing of continuous flax-fibre based shape-changing hygromorph biocomposites: Towards sustainable metamaterials[J/OL]. Materials and Design, 2021, 211: 110158.
[82] CHEN H, ZHANG F, SUN Y, et al. Electrothermal shape memory behavior and recovery force of four-dimensional printed continuous carbon fiber/polylactic acid composite[J/OL]. Smart Materials and Structures, 2021, 30(2): 025040.
[83] PUTHANVEETIL S, LIU W C, RILEY K S, et al. Programmable multistability for 3D printed reinforced multifunctional composites with reversible shape change[J/OL]. Composites Science and Technology, 2022, 217: 109097.
[84] CORREA D, PAPADOPOULOU A, GUBERAN C, et al. 3D-Printed Wood: Programming Hygroscopic Material Transformations[J/OL]. 3D Printing and Additive Manufacturing, 2015, 2(3): 106-116.
[85] CORREA D, POPPINGA S, MYLO M D, et al. 4D pine scale: Biomimetic 4D printed autonomous scale and flap structures capable of multi-phase movement[J/OL]. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, 2020, 378(2167): 20190445.
[86] KRÜGER F, THIERER R, TAHOUNI Y, et al. Development of a material design space for 4d-printed bio-inspired hygroscopically actuated bilayer structures with unequal effective layer widths[J/OL]. Biomimetics, 2021, 6(4): 58-69.
[87] CHENG T, THIELEN M, POPPINGA S, et al. Bio-Inspired Motion Mechanisms: Computational Design and Material Programming of Self-Adjusting 4D-Printed Wearable Systems[J/OL]. Advanced Science, 2021, 8(13): 2100411.
[88] MULAKKAL M C, TRASK R S, TING V P, et al. Responsive cellulose-hydrogel composite ink for 4D printing[J/OL]. Materials and Design, 2018, 160: 108-118.
[89] ZHOU Y, YANG Y, JIAN A, et al. Co-extrusion 4D printing of shape memory polymers with continuous metallic fibers for selective deformation[J/OL]. Composites Science and Technology, 2022, 227(May): 109603.
[90] WEI H, CAUCHY X, NAVAS I O, et al. Direct 3D Printing of Hybrid Nanofiber-Based Nanocomposites for Highly Conductive and Shape Memory Applications[J/OL]. ACS Applied Materials and Interfaces, 2019, 11(27): 24523-24532.
[91] GLADMAN A S, MATSUMOTO E A, NUZZO R G, et al. Biomimetic 4D printing[J/OL]. 2016, 15(April): 413-418.
[92] LIU Q, SMALYUKH I I. Liquid crystalline cellulose-based nematogels[J/OL]. Science Advances, 2017, 3(8): e1700981.
[93] ZHAO N, WANG X, YAO L, et al. Actuation performance of a liquid crystalline elastomer composite reinforced by eiderdown fibers[J/OL]. Soft Matter, 2022, 18(6): 1264-1274.
[94] HUANG Y Y, BIGGINS J, JI Y, et al. Mechanical bistability in liquid crystal elastomer-wire composite actuators[J/OL]. Journal of Applied Physics, 2010, 107(8): 083515.
[95] HE Q, WANG Z, SONG Z, et al. Bioinspired Design of Vascular Artificial Muscle[J/OL]. Advanced Materials Technologies, 2019, 4(1): 1800244