Controllable bistable smart composite structures driven by liquid crystal elastomer

Abstract

In this article, we proposed a new way to achieve monostable and bistable characteristics of composite layers based on liquid crystal elastomer (LCE). A smart trilayer composite structure is fabricated using LCE and acrylic elastomer, which can have several morphologies. It keeps flat at room temperature and can deform into a monostable saddle or bistable cylinder surface in response to simple temperature changes. The reversible deformation can be controlled through two parameters including geometrical size and actuation strain. The LCE can be programmed to generate different actuation strains by different formulas during synthesis or different mechanical stretches during UV radiation. The deformed morphology for different sample sizes and actuation strain is calculated using Finite element simulation. By comparison with the experimental results, we confirm that the phenomena can be captured through numerical simulations. Furthermore, to have a quantitative understanding, we use numerical simulation to calculate the deformation of the composite structure by tuning these two parameters and give a morphological portrait illustrating the relationship between the deformed shape and control parameters.

Bistable and Multistable Actuators for Soft Robots: Structures, Materials, and Functionalities

“…Varieties of bioinspired bistable curved plate‐based soft active actuators have been created made of different stimuli‐responsive materials such as dielectric elastomers, hydrogels, and LCPs. [ 206,213–216 ] For example, Shao et al. [ 211 ] proposed using electric actuation to trigger snap‐through instabilities in 2D curved plate‐based soft dielectric actuators (Figure 13E).…”

“…Varieties of bioinspired bistable curved plate-based soft active actuators have been created made of different stimuli-responsive materials such as dielectric elastomers, hydrogels, and LCPs. [206,[213][214][215][216] For example, Shao et al [211] proposed using electric actuation to trigger snap-through instabilities in 2D curved plate-based soft dielectric actuators (Figure 13E). The soft bistable actuators were fabricated by bonding two orthogonally pre-strained dielectric films (VHB) onto two sides of a stiff yet flexible support layer (polyimide (PI) or polyester (PET) films) with embedded compliant electrodes in between (Figure 13E-i).…”

Multiphysics modeling for pressure-thermal sensitive hydrogels

“…which is additionally influenced by the hydrostatic pressure P. Similar to eqn (5), ds is the entropy change per monomeric unit of networks and dh is the enthalpy change per monomeric unit of networks. Differently, an additional term of w 2 (T)P is introduced into eqn ( 6) and w 1 is no longer a constant but a function of P. Moreover, w 1 (P) = A À BP and w 2 (T) = (a À bT)/(k B T) are two common adopted linear functions for w 1 and w 2 , respectively.…”

“…The stimuli can roughly be categorized into physical, chemical, and biomechanical factors. The physical stimuli include temperature, 1 electric fields, 2 magnetic fields, 3 light, 4,5 pressure, 6 and sound, 7 while the chemical and biochemical stimuli include pH, 8 enzymes, 9 and glucose. 10 The large tunable deformation of hydrogel networks can be achieved by absorbing or expelling solvent molecules induced by external stimuli.…”

Shape Morphing of 3D Printed Liquid Crystal Elastomer Structures with Precuts

“…The LCEs can exhibit complex shape transformations by carefully programming the geometries and orientation patterns. − Peng et al proposed an approach for realizing 4D printing of freestanding LCE by the integration of laser-assisted DIW and DLP, which provide design freedom and fabrication capability for applications. Wang et al prepared a photothermal composite ink AuNR/LCE and demonstrated that 3D-printed AuNR/LCE flower whose petals can be “bloomed” globally or individually.…”