One-Step Soaking Approach for the Development of High-Strength, Tough Silicone Hydrogels with Elevated Polysiloxane Content

Abstract

Silicone hydrogels (SiHys) present a variety of promising applications. However, their intrinsic mechanical limitations and low silicone content often restrict their practical use. In this study, we propose a simple and versatile one-step soaking strategy to produce double-network SiHys with high silicone content and enhanced mechanical strength and toughness. Hydrophobic amino-modified polydimethylsiloxane (APDMS) becomes hydrophilic through a “salt-forming” reaction with acetic acid (HAc), enabling substantial incorporation within a poly(vinyl alcohol) (PVA) network. This is followed by a one-step soaking in a polyhydric-acid salt aqueous solution, facilitating the in situ formation of a physically cross-linked APDMS network via acid exchange. By controlling the feed concentration of APDMS and the types of polyhydric-acid salts employed, we can fine-tune the hydrogel’s aggregated structural characteristics and the strength of intermolecular electrostatic interactions, thereby enabling a wide range of tunability in the mechanical properties of the SiHys. This study innovatively establishes a simple and universal technique for preparing silicon-based hydrogels with high mechanical performance and silicone content, advancing the development of silicon-based hydrogels.