Catalytic vs. thermal Si - H crosslinking polydimethylsiloxane (PDMS) elastomers: Network heterogeneity drives...

Network architecture in PDMS elastomers, determined by the crosslinking pathway, plays a key role in governing interfacial performance. It remains unclear how uniform versus heterogeneous networks influence energy dissipation, adhesion, and ice detachment on soft elastomer surfaces. This study aims to establish a direct link between crosslinking chemistry, network structure, and interfacial behavior.

A single-component, solvent-free PDMS system based on multifunctional hydrosiloxane precursors was crosslinked via two routes: platinum-catalyzed hydrosilylation at low temperature and additive-free thermal curing at elevated temperature. The resulting networks were characterized using spectroscopic, rheological, and morphological analyses. Interfacial performance was evaluated through peeling tests on polymer films, sliding angle measurements, and ice adhesion tests at subzero temperatures.

Catalytic curing produced uniform, densely crosslinked networks with tunable adhesion (70-550 mN/m) and moderate ice adhesion (∼20 kPa at -30 °C), which remain advantageous for most practical applications. Thermal curing generated heterogeneous architectures with enhanced surface topography and local chain mobility, consequently, these samples exhibited lower peeling strength (64 mN/m), reduced ice adhesion (∼15 kPa), and minimal contact line pinning. These structural differences translate into distinct energy dissipation modes at the solid-liquid interface, providing mechanistic insight for designing sustainable, low-adhesion elastomers for anti-icing, antifouling, and other soft-interface applications.