Anisotropic Bi-Layer Hydrogel Actuator with pH-Responsive Color-Changing and Photothermal-Responsive Shape-Changing Bi-Functional Synergy
Chao Ma,
Shuyi Peng,
Lian Chen,
Xingyu Cao,
Ye Sun,
Lin Chen,
Lang Yang,
Chunming Ma,
Qijie Liu,
Zhenzhong Liu,
Shaohua Jiang
Affiliations
Chao Ma
State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, Haikou 570228, China
Shuyi Peng
State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, Haikou 570228, China
Lian Chen
Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, International Innovation Center for Forest Chemicals and Materials, College of Materials Science and Engineering, Nanjing Forestry University, Nanjing 210037, China
Xingyu Cao
State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, Haikou 570228, China
Ye Sun
State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, Haikou 570228, China
Lin Chen
State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, Haikou 570228, China
Lang Yang
State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, Haikou 570228, China
Chunming Ma
Shenzhen Institute of Advanced Electronic Materials—Shenzhen Fundamental Research Institutions, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
Qijie Liu
Taizhou Key Laboratory of Medical Devices and Advanced Materials, Research Institute of Zhejiang University, Taizhou 318000, China
Zhenzhong Liu
Taizhou Key Laboratory of Medical Devices and Advanced Materials, Research Institute of Zhejiang University, Taizhou 318000, China
Shaohua Jiang
Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, International Innovation Center for Forest Chemicals and Materials, College of Materials Science and Engineering, Nanjing Forestry University, Nanjing 210037, China
Stimuli-responsive color-changing and shape-changing hydrogels are promising intelligent materials for visual detections and bio-inspired actuations, respectively. However, it is still an early stage to integrate the color-changing performance and shape-changing performance together to provide bi-functional synergistic biomimetic devices, which are difficult to design but will greatly expand further applications of intelligent hydrogels. Herein, we present an anisotropic bi-layer hydrogel by combining a pH-responsive rhodamine-B (RhB)-functionalized fluorescent hydrogel layer and a photothermal-responsive shape-changing melanin-added poly (N-isopropylacrylamide) (PNIPAM) hydrogel layer with fluorescent color-changing and shape-changing bi-functional synergy. This bi-layer hydrogel can obtain fast and complex actuations under irradiation with 808 nm near-infrared (NIR) light due to both the melanin-composited PNIPAM hydrogel with high efficiency of photothermal conversion and the anisotropic structure of this bi-hydrogel. Furthermore, the RhB-functionalized fluorescent hydrogel layer can provide rapid pH-responsive fluorescent color change, which can be integrated with NIR-responsive shape change to achieve bi-functional synergy. As a result, this bi-layer hydrogel can be designed using various biomimetic devices, which can show the actuating process in the dark for real-time tracking and even mimetic starfish to synchronously change both the color and shape. This work provides a new bi-layer hydrogel biomimetic actuator with color-changing and shape-changing bi-functional synergy, which will inspire new strategies for other intelligent composite materials and high-level biomimetic devices.
