Gradient Diffusion Anisotropic Carboxymethyl Cellulose Hydrogels for Strain Sensors

• Published in: Biomacromolecules 2021-12, Vol.22 (12), p.5033-5041
• Main Authors: Ouyang, Kangwen, Zhuang, Jie, Chen, Chuchu, Wang, Xuerong, Xu, Mengting, Xu, Zhaoyang
• Format: Article
• Language: English
• Subjects: Carboxymethylcellulose Sodium - chemistry; Humans; Hydrogels - chemistry; Wearable Electronic Devices
• ISSN: 1525-7797; 1526-4602
• DOI: 10.1021/acs.biomac.1c01003

Recently, because of the unique properties of anisotropic and isotropic structures, there are more research studies on anisotropic hydrogels. We prepared a gradient anisotropic carboxymethyl cellulose hydrogel (CMC-Al3+) by directionally diffusing aluminum chloride solution. The orientation of carboxymethyl cellulose (CMC) chains is perpendicular to the direction of aluminum ion diffusion. The degree of cross-linking and orientation gradually decrease along the direction of aluminum ion diffusion. Compared with anisotropic hydrogels prepared by other methods, the hydrogels prepared by directionally diffusing aluminum ion solution have a gradient lamellar structure. Because of the large amount of aluminum ions in CMC-Al3+, the hydrogel shows good sensing performance. CMC-Al3+ is packaged with PVC electrical flame retardant tape to produce a strain sensor used to detect human tiny movements, which can accurately and stably monitor tiny movements. Hydrogel-based strain sensors can be widely used in the fields of human–computer intelligence, human–computer interaction, and wearable devices in the future.