Jang, Minsu Kim, Jun Sik Kim, Ji-Hun Bae, Do Hyun Kim, Min Jun Son, Donghee Kim, Yong-Tae Um, Soong Ho Kim, Yong Ho Kim, Jinseok 2024-01-19T20:30:50Z 2024-01-19T20:30:50Z 2021-09-02 2019-04 2073-4360 https://pubs.kist.re.kr/handle/201004/120147 Polymer actuators are important components in lab-on-a-chip and micromechanical systems because of the inherent properties that result from their large and fast mechanical responses induced by molecular-level deformations (e.g., isomerization). They typically exhibit bending movements via asymmetric contraction or expansion with respect to changes in environmental conditions. To enhance the mechanical properties of actuators, a strain gradient should be introduced by regulating the molecular alignment; however, the miniaturization of polymer actuators for microscale systems has raised concerns regarding the complexity of such molecular control. Herein, a novel method for the fabrication of micro-actuators using a simple molecular self-alignment method is presented. Amphiphilic molecules that consist of azobenzene mesogens were located between the hydrophilic and hydrophobic surfaces, which resulted in a splayed alignment. Thereafter, molecular isomerization on the surface induced a large strain gradient and bending movement of the actuator under ultraviolet-light irradiation. Moreover, the microelectromechanical systems allowed for the variation of the actuator size below the micron scale. The mechanical properties of the fabricated actuators such as the bending direction, maximum angle, and response time were evaluated with respect to their thicknesses and lengths. The derivatives of the polymer actuator microstructure may contribute to the development of novel applications in the micro-robotics field. English MDPI PHOTOINDUCED BENDING BEHAVIOR CRYSTAL NETWORK ACTUATORS LIGHT COMPOSITE DRIVEN MOTION Surface-Controlled Molecular Self-Alignment in Polymer Actuators for Flexible Microrobot Applications Article 10.3390/polym11040736 1 POLYMERS, v.11, no.4 POLYMERS 11 4 scie scopus 000467312900165 2-s2.0-85065902181 Polymer Science Polymer Science Article PHOTOINDUCED BENDING BEHAVIOR CRYSTAL NETWORK ACTUATORS LIGHT COMPOSITE DRIVEN MOTION polymer actuator self-alignment azobenzene microelectromechanical systems