Ambient Solvent Evaporation-Triggered Irreversible Covalent Crosslinking for Robust Adhesion in Extreme Conditions

Abstract

Covalently crosslinked polymers, renowned for their stability and superior performance, play a pivotal role in materials science and technology. Yet, conventional crosslinking, reliant on external agents and energy-intensive processes, prompts a growing demand for sustainable and energy-efficient alternatives. Here, it is demonstrated that irreversible covalent crosslinking can be achieved simply through ambient solvent evaporation in a molecularly engineered polydimethylsiloxane system functionalized with dithiolane moieties. This process, validated using reduced density gradient analysis, forms a robust, irreversible covalent polymer network (CTP), fundamentally distinct from conventional dynamic disulfide-based reversible crosslinking systems or physically bonded polymers typically formed via solvent evaporation. The resultant CTP demonstrates strong adhesion to various substrates, as analyzed quantitatively through Density Functional Theory simulations. Furthermore, the CTP displays excellent waterproofing, high optical transparency, and notable resistance to extreme temperatures and highly corrosive solvents. The superior performance of CTP derives from its robust covalent network, enriched with disulfide and peptide bonds and liquid-like PDMS segments. Moreover, the CTP's preparation is straightforward, sustainable, and cost-effective. These advancements position CTP as a promising development in adhesive technology, suitable for a wide range of applications requiring mechanical robustness, chemothermal resilience, and optical clarity, particularly in scenarios sensitive to thermal or radiation exposure.