Tough and Thermosensitive Poly(N-isopropylacrylamide)/Graphene Oxide Hydrogels with Macroscopically Oriented Liquid Crystalline Structures
| Autor: | Cong Shang, Hui Xu, Ya-Nan Chen, Zhongcheng Zhu, Xin Peng, Huiliang Wang, Qin Zhang, Jiaqi Liu, Yang Li |
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| Rok vydání: | 2016 |
| Předmět: |
Phase transition
Materials science Nanocomposite Graphene Oxide 02 engineering and technology 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences 0104 chemical sciences law.invention chemistry.chemical_compound chemistry law Ultimate tensile strength Self-healing hydrogels Poly(N-isopropylacrylamide) General Materials Science In situ polymerization Composite material 0210 nano-technology |
| Zdroj: | ACS Applied Materials & Interfaces. 8:15637-15644 |
| ISSN: | 1944-8252 1944-8244 |
| Popis: | Bulk graphene oxide (GO) nanocomposite materials with macroscopically oriented GO liquid crystalline (LC) structures exhibit interesting anisotropic properties, but their facile preparations remain challenging. This work reports for the first time the facile preparation of poly(N-isopropylacrylamide) (PNIPAM)/GO nanocomposite hydrogels with macroscopically oriented LC structures with the assistance of a flow field induced by vacuum degassing and the in situ polymerization accelerated by GO. The hydrogel prepared with a GO concentration of 5.0 mg mL(-1) exhibits macroscopically aligned LC structures, which endow the gels with anisotropic optical, mechanical properties, and dimensional changes during the phase transition. The hydrogels show dramatically enhanced tensile mechanical properties and phase transition rates. The oriented LC structures are not damaged during the phase transition of the PNIPAM/GO hydrogels, and hence their LC behavior undergoes reversible change. Moreover, highly oriented LC structures can also be formed when the gels are elongated, even for the gels which do not have macroscopically oriented LC structures. Very impressively, the oriented LC structures in the hydrogels can be permanently maintained by drying the gel samples elongated to and then kept at a constant tensile strain. The thermosensitive nature of PNIPAM and the angle-dependent nature of the macroscopically aligned GO LC structures allow the practical applications of the PNIPAM/GO hydrogels as optical switches, soft sensors, and actuators and so on. |
| Databáze: | OpenAIRE |
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