Enhanced Interfacial Adhesion of Polydimethylsiloxane (PDMS) by Control of the Crosslink Density

In this paper, we report a simple, fast, and one-step approach to improve the adhesion force of polydimethylsiloxane (PDMS) by incorporating inorganic nanoparticles that can control the physical, mechanical, and adhesion properties of the PDMS. An organic/inorganic PDMS-based composite was fabricated by the hydrosilylation of vinyl-decorated silica nanoparticles (v-SNPs) and the PDMS. The v-SNP/PDMS composite showed a significantly decreased elastic modulus and increased elongation compared with that of pristine SNPs incorporated with the PDMS composite (SNP/PDMS) and pristine PDMS. Furthermore, the v-SNP/PDMS composite exhibited a low glass-transition temperature and sharp crystallization and melting peaks in the differential scanning calorimetry curve compared with those of pristine PDMS and the SNP/PDMS composite. Moreover, the v-SNP/PDMS composite showed a high swelling ratio and crosslinked molecular weight and low gel fraction. These results may originate from the suppression of the PDMS-curing networks as the addition of the v-SNPs creates a low curing density because of the chemical bonding between PDMS and the v-SNPs. Finally, the v-SNP/PDMS composite showed an improvement of ~426% in the adhesion force compared with pristine PDMS and the SNP/PDMS composite. We anticipate that this v-SNP/PDMS composite could be used as a highly adhesive and hydrophobic coating material for various applications in industry.