Direct-Ink-Writing of Dual-Responsive Liquid Crystal Elastomers = 직접 잉크 쓰기 방식을 적용한 이중 자극 응답형 액정 탄성체의 3D 프린팅

다국어 초록 (Multilingual Abstract)

Liquid crystal elastomers (LCEs) are stimuli-responsive actuating materials that undergo reversible shape changes upon exposure to external stimuli. LCEs are promising alternatives for conventional actuators owing to the versatility of accepted stimuli and simple processing methods, such as extrusion-based three-dimensional (3D) printing. Recently, several double-layered polymer-LCE composites responding to one or more stimuli were fabricated by combining two materials. However, few reports are available regarding the fabrication of single-layered soft LCEs that respond to two different stimuli via 3D printing. Such LCE can be customized to adapt to diverse environments by simply varying the printing geometries of the single layer. In this study, the chemical composition of the liquid crystal ink was investigated to determine the optimal formulation for fabricating an LCE that responds to both relatively low temperatures and moisture. Subsequently, the optimized ink was used for direct-ink-writing-based 3D printing and subsequent ultraviolet crosslinking, yielding dual-stimuli-responsive LCEs (dual-LCEs). Subsequently, the shape transformations in response to heat and moisture were examined using uniaxially aligned monodomain LCEs. Importantly, the as-fabricated four-petal flower-shaped LCE actuator exhibited two different shape transformations toward heat and moisture, thereby demonstrating the potential of the as-developed dual-LCEs for application in soft robotics or actuators.

목차 (Table of Contents)

• Abstract 1
• 1. Introduction 2
• 2. Experimental Section 5
• 2.1 Materials 5
• 2.2 Preparation of LC oligomers 5
• 2.3 Direct-Ink-Writing of Dual-LCEs 5
• 2.4 Methods and Characterization 6
• 2.5 Viscoelastic and Thermomechanical Properties 6
• 2.6 Steady-Shear viscosity 7
• 3. Result and Discussion 8
• 4. Conclusions 13
• 5. References 14
• 요약 32