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You Y, Golestani YM, Broer DJ, Yang T, Zhou G, Selinger RLB, Yuan D, Liu D. Transforming patterned defects into dynamic poly-regional topographies in liquid crystal oligomers. MATERIALS HORIZONS 2024; 11:3178-3186. [PMID: 38666445 PMCID: PMC11216033 DOI: 10.1039/d4mh00131a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Accepted: 04/18/2024] [Indexed: 07/02/2024]
Abstract
We create high-aspect-ratio dynamic poly-regional surface topographies in a coating of a main-chain liquid crystal oligomer network (LCON). The topographies form at the topological defects in the director pattern organized in an array which are controlled by photopatterning of the alignment layer. The defect regions are activated by heat and/or light irradiation to form reversible topographic structures. Intrinsically, the LCON is rubbery and sensitive to temperature changes, resulting in shape transformations. We further advanced such system to make it light-responsive by incorporating azobenzene moieties. Actuation reduces the molecular order of the LCON coating that remains firmly adhered to the substrate which gives directional shear stresses around the topological defects. The stresses relax by deforming the surfaces by forming elevations or indents, depending on the type of defects. The formed topographies exhibit various features, including two types of protrusions, ridges and valleys. These poly-regional structures exhibit a large modulation amplitude of close to 60%, which is 6 times larger than the ones formed in liquid crystal networks (LCNs). After cooling or by blue light irradiation, the topographies are erased to the initial flat surface. A finite element method (FEM) model is adopted to simulate structures of surface topographies. These dynamic surface topographies with multilevel textures and large amplitude expand the application range, from haptics, controlled cell growth, to intelligent surfaces with adjustable adhesion and tribology.
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Affiliation(s)
- Yuxin You
- Joint Research Lab of Devices Integrated Responsive Materials (DIRM), South China Normal University, Guangzhou 510006, China.
- Human Interactive Materials (HIM), Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, Groene Loper 3, Eindhoven 5612AE, The Netherlands.
- Institute for Complex Molecular Systems (ICMS), Eindhoven University of Technology, Groene Loper 3, Eindhoven 5612AE, The Netherlands
| | - Youssef M Golestani
- Human Interactive Materials (HIM), Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, Groene Loper 3, Eindhoven 5612AE, The Netherlands.
- Institute for Complex Molecular Systems (ICMS), Eindhoven University of Technology, Groene Loper 3, Eindhoven 5612AE, The Netherlands
| | - Dirk J Broer
- Human Interactive Materials (HIM), Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, Groene Loper 3, Eindhoven 5612AE, The Netherlands.
- Institute for Complex Molecular Systems (ICMS), Eindhoven University of Technology, Groene Loper 3, Eindhoven 5612AE, The Netherlands
| | - Tinghong Yang
- Joint Research Lab of Devices Integrated Responsive Materials (DIRM), South China Normal University, Guangzhou 510006, China.
| | - Guofu Zhou
- Joint Research Lab of Devices Integrated Responsive Materials (DIRM), South China Normal University, Guangzhou 510006, China.
| | - Robin L B Selinger
- Department of Physics, Kent State University, Kent, OH 44242, USA.
- Advanced Materials and Liquid Crystal Institute, Kent State University, Kent, OH 44242, USA
| | - Dong Yuan
- Joint Research Lab of Devices Integrated Responsive Materials (DIRM), South China Normal University, Guangzhou 510006, China.
| | - Danqing Liu
- Human Interactive Materials (HIM), Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, Groene Loper 3, Eindhoven 5612AE, The Netherlands.
- Institute for Complex Molecular Systems (ICMS), Eindhoven University of Technology, Groene Loper 3, Eindhoven 5612AE, The Netherlands
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Jin B, Chen G, Chen Y, Yang C, Zhu Z, Weng Y, Zhao Q, Xie T. Reprogramming Photoresponsive Liquid Crystalline Elastomer via Force-Directed Evaporation. ACS APPLIED MATERIALS & INTERFACES 2024; 16:16844-16852. [PMID: 38517683 DOI: 10.1021/acsami.4c01076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/24/2024]
Abstract
Incorporating photothermal agents into thermoresponsive liquid crystalline elastomers (LCEs) offers remote and spatio-temporal control in actuation. Typically, both the light responsiveness and actuation behaviors are fixed since the agent doping and mesogen alignment are conducted before network formation. Here, we report an approach that enables programming photoresponsive LCEs after synthesis via force-directed evaporation. Different photothermal agents can be doped or removed by swelling the fully cross-linked LCEs in a specific solution, achieving the introduction and erasing of the photoresponsiveness. Moreover, the network swelling deletes the registered alignment, which allows for redefining the molecular order via re-evaporating the solvent with force imposed. This "one stone, two birds" strategy paves the way to simultaneously program/reprogram the actuation mode and responsiveness of LCEs, even in a spatio-selective manner to achieve complex actuations. Our approach is expandable to three-dimensional (3D) printed LCEs to access geometrically sophisticated shape-changing.
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Affiliation(s)
- Binjie Jin
- State Key Laboratory of Chemical Engineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China
- Center for X-Mechanics, Department of Engineering Mechanics, Zhejiang University, Hangzhou 310027, China
| | - Guancong Chen
- State Key Laboratory of Chemical Engineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China
| | - Yishu Chen
- State Key Laboratory of Chemical Engineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China
| | - Chen Yang
- State Key Laboratory of Chemical Engineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China
| | - Zhan Zhu
- State Key Laboratory of Chemical Engineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China
| | - Yunhao Weng
- State Key Laboratory of Chemical Engineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China
| | - Qian Zhao
- State Key Laboratory of Chemical Engineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China
| | - Tao Xie
- State Key Laboratory of Chemical Engineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China
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