Layered Hydrogel with Controllable Surface Dissociation for Durable Lubrication
Minghai Qu, Hui Liu, Changyou Yan, Shuanhong Ma, Meirong Cai, Zhengfeng Ma, Feng Zhou
Abstract
Developing bioinspired hydrogel materials with extraordinary lubrication, load-bearing, and antiwear property is necessary for durable lubricious implants or devices. Despite the extensive research focus on lubrication of hydrogel materials, achieving a balance between lubrication and load-bearing for the current system is commonly difficult because of their poor mechanical property. Herein, a cartilage-inspired layered hydrogel material composed of a soft and porous top layer and a robust bottom layer is easily prepared by employing an alkali-induced network dissociation strategy. The thickness of the top soft layer increases with extending the alkali treatment time, along with differential surface and cross-sectional morphologies and mechanical property. The top soft and porous layer ensures that the surface shows extremely low friction (coefficient of friction (COF) ∼ 0.009, 3 N; COF ∼ 0.035, 20 N) against a hard steel ball contact pair, while the bottom layer acts as an excellent load-bearing function. Therefore, the layered hydrogels can achieve extraordinary wear resistance features, resulting from a combination of surface lubrication and bottom load-bearing. It is demonstrated that the method can be used to develop a layered hydrogel lubrication catheter, for which both of its inner and outer surfaces exhibit a slippery feature. The extraordinary lubricious performance of the layered hydrogels implies their potential application in the field of tissue engineering and medical devices.