Durable liquid-crystalline vitrimer actuators

Chen, Qiaomei; Li, Yongsan; Yang, Yang; Xu, Yanshuang; Qian, Xiaojie; Wei, Yen; Ji, Yan

doi:10.1039/c8sc05358h

“…Vitrimers are able to change their topological structure due to the exchange reactions under certain external stimuli. To date, most of the monodomain LCPs with exchangeable links were prepared based on transesterification [45][46][47], transcarbamoyalation [48], boronic-ester bond [49], disulfide [50,51], and allyl sulfide groups [52][53][54]. Summarized in Figure 2, Ji et al demonstrated that after programming the LCEs monodomain with the topological network rearrangement were facilitated by thermo-induced transesterification.…”

Section: Strategy For Preparation Of Monodomain Lcpsmentioning

confidence: 99%

A Review on Liquid Crystal Polymers in Free-Standing Reversible Shape Memory Materials

Wen

¹

,

Yang

²

,

Raquez

³

2020

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Liquid crystal polymers have attracted massive attention as stimuli-responsive shape memory materials due to their unique reversible large-scale and high-speed actuations. These materials can be utilized to fabricate artificial muscles, sensors, and actuators driven by thermal order–disorder phase transition or trans–cis photoisomerization. This review collects most commonly used liquid crystal monomers and techniques to macroscopically order and align liquid crystal materials (monodomain), highlighting the unique materials on the thermal and photo responsive reversible shape memory effects. Challenges and potential future applications are also discussed.

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“…In all of the previous systems, as long as thermally triggered bond exchange exists, the risk of actuation loss and shape distortion always exists at work and in storage, which is not satisfactory for applications that demand creep resistance at elevated temperature. The unwanted thermally induced bond exchange can be slowed down, but it cannot be eliminated …”

Section: Introductionmentioning

confidence: 99%

Liquid‐Crystalline Soft Actuators with Switchable Thermal Reprogrammability

Wu

¹

,

Yang

²

,

Qian

³

et al. 2020

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Thermal reprogrammability is essential for new‐generation large dry soft actuators, but the realization sacrifices the favored actuation performance. The contradiction between thermal reprogrammability and stability hampers efforts to design high‐performance soft actuators to be robust and thermally adaptable. Now, a strategy has been developed that relies on repeatedly switching on/off thermal reprogrammability in liquid‐crystalline elastomer (LCE) actuators to resolve this problem. By post‐synthesis swelling, a latent siloxane exchange reaction can be induced in the common siloxane LCEs (switching on), enabling reprogramming into on‐demand 3D‐shaped actuators; by switching off the dynamic network by heating, actuation stability is guaranteed even at high temperature (180 °C). Using partially black‐ink‐patterned LCEs, selectively switching off reprogrammability allows integration of completely different actuation modes in one monolithic actuator for more delicate and elaborate tasks.

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“…However, as for the aligned actuator in which TMA‐DMSiO had not been deactivated, degradation of thermal actuation was obviously observed after the first cooling–heating cycle (Supporting Information, Figure S17). Notably, our strategy to switch off network dynamics for attaining thermal and actuation stability is essentially different from the previous strategies that just slow down the bond exchange rate at high temperatures in LCEs . Our strategy directly eliminates the siloxane bond exchangeability in the network.…”

Section: Resultsmentioning

confidence: 98%

Liquid‐Crystalline Soft Actuators with Switchable Thermal Reprogrammability

Wu

¹

,

Yang

²

,

Qian

³

et al. 2020

Self Cite

View full text Add to dashboard Cite

Thermal reprogrammability is essential for new‐generation large dry soft actuators, but the realization sacrifices the favored actuation performance. The contradiction between thermal reprogrammability and stability hampers efforts to design high‐performance soft actuators to be robust and thermally adaptable. Now, a strategy has been developed that relies on repeatedly switching on/off thermal reprogrammability in liquid‐crystalline elastomer (LCE) actuators to resolve this problem. By post‐synthesis swelling, a latent siloxane exchange reaction can be induced in the common siloxane LCEs (switching on), enabling reprogramming into on‐demand 3D‐shaped actuators; by switching off the dynamic network by heating, actuation stability is guaranteed even at high temperature (180 °C). Using partially black‐ink‐patterned LCEs, selectively switching off reprogrammability allows integration of completely different actuation modes in one monolithic actuator for more delicate and elaborate tasks.

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Durable liquid-crystalline vitrimer actuators

Abstract: A vitrimer-based LCE actuator subtly mitigates the conflict between processability and actuation durability by reducing the catalyst content.

Cited by 88 publications

References 38 publications

A Review on Liquid Crystal Polymers in Free-Standing Reversible Shape Memory Materials

A Review on Liquid Crystal Polymers in Free-Standing Reversible Shape Memory Materials

Liquid‐Crystalline Soft Actuators with Switchable Thermal Reprogrammability

Liquid‐Crystalline Soft Actuators with Switchable Thermal Reprogrammability

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