Zhang Xinmeng, Yao Yuanyuan, Wu Yu, Liu Wenjing, Wang Xunwei, Feng Peizhong, Zhang Jianming, Hu Wu, Shang Erdong
School of Materials Science and Engineering, Shaanxi Key Laboratory of Green Preparation and Functionalization for Inorganic Materials, Shaanxi University of Science & Technology, Xi'an 710021, China; School of Materials and Physics, China University of Mining and Technology, Xuzhou 221116, China; Ningbo Hantech Medical Device CO., LTD, Ningbo 315326, China.
School of Materials Science and Engineering, Shaanxi Key Laboratory of Green Preparation and Functionalization for Inorganic Materials, Shaanxi University of Science & Technology, Xi'an 710021, China.
J Colloid Interface Sci. 2025 Feb;679(Pt B):79-90. doi: 10.1016/j.jcis.2024.10.076. Epub 2024 Oct 16.
Highly flexible hydrogels are widely used in fields such as agriculture, drug delivery, and tissue engineering. However, the simultaneous integration of excellent mechanical properties, swelling properties, and high electrical conductivity into a hydrogel is still a great challenge. This work introduces 1D tubular multi-walled carbon nanotubes (MWCNTs) and 2D layered graphene oxide (GO) into polyacrylamide/poly-acrylic acid (PAM/PAA) hydrogels. The high specific surface area and oxygen-containing groups of GO contribute to excellent mechanical properties and water absorption of the PAM/PAA hydrogels, but the conductivity is poorly affected due to the presence of defects on GO surface. However, MWCNTs with large aspect ratios benefit to form continuous conductive paths in PAM/PAA hydrogels which further improves conductivity of the hydrogels. MWCNTs are entangled with PAM/PAA molecular chains to form a dense three-dimensional (3D) network structure, and this special structure improves the water absorption of PAM/PAA hydrogels by 3.7 g g. What's more, the MWCNTs/PAM/PAA hydrogel not only provides excellent mechanical properties (compressive strength up to 2.7 MPa), but also has high conductivity (2.3 S m). In particular, a strain sensor based on MWCNTs/PAM/PAA hydrogel exhibits exceptional sensitivity (gauge factor = 3.9 at 230-300 % strain) with a rapid response (200 ms) over a wide strain range (50 ∼ 200 %) which enables the ability to precisely and reliably monitor human motion. Therefore, the work provides a new insight into the design of multifunctional hydrogels with application on anatomical water plugging, electronic skin, and biosensors.
高柔韧性水凝胶广泛应用于农业、药物递送和组织工程等领域。然而，将优异的机械性能、溶胀性能和高电导率同时集成到水凝胶中仍然是一个巨大的挑战。这项工作将一维管状多壁碳纳米管（MWCNTs）和二维层状氧化石墨烯（GO）引入聚丙烯酰胺/聚丙烯酸（PAM/PAA）水凝胶中。GO的高比表面积和含氧基团有助于PAM/PAA水凝胶具有优异的机械性能和吸水性，但由于GO表面存在缺陷，其导电性受到不利影响。然而，具有大长径比的MWCNTs有利于在PAM/PAA水凝胶中形成连续的导电路径，从而进一步提高水凝胶的导电性。MWCNTs与PAM/PAA分子链缠结形成致密的三维（3D）网络结构，这种特殊结构使PAM/PAA水凝胶的吸水量提高了3.7 gg。此外，MWCNTs/PAM/PAA水凝胶不仅具有优异的机械性能（抗压强度高达2.7 MPa），还具有高导电性（2.3 S m）。特别是，基于MWCNTs/PAM/PAA水凝胶的应变传感器在宽应变范围（50 ∼ 200%）内表现出卓越的灵敏度（在230 - 300%应变下的应变系数 = 3.9）和快速响应（200 ms），能够精确可靠地监测人体运动。因此，这项工作为设计用于解剖堵漏、电子皮肤和生物传感器的多功能水凝胶提供了新的思路。
