Tunable composite architecture and homogeneous dispersion of charged SiO2 in polymer matrix assisted by poly(2-ethylhexyl acrylate) (P2EHA) latex prepared by self-assembly through electrostatic interactions

Abstract

We report a simple and environmentally friendly approach for preparing a homogeneous dispersion of poly(2-ethylhexyl acrylate)–silicon dioxide (P2EHA–SiO₂) composites by self-assembly of negatively charged P2EHA and charged SiO₂. The P2EHA latex particles were prepared by miniemulsion polymerization using a free-radical initiator. As auxiliary monomer, acrylic acid created the positive charges on the surface of the P2EHA latex. By mixing P2EHA latex particles with positively charged SiO₂ (pSiO₂) particles, negatively charged P2EHA latex particles easily assembled with pSiO₂ particles through electrostatic interactions. The presence of P2EHA latex particles assisted the homogeneous dispersion of pSiO₂ particles in the polymer matrix. After film formation process, the film exhibited excellent thermal-tolerance and adhesive properties. A three-component system of P2EHA latex particles, pSiO₂, and negatively charged SiO₂ (nSiO₂) was also achieved successfully due to the mutual assistance effect. A better thermal-tolerance and adhesive properties were obtained. Through the establishment of the film formation mechanism, we found that the architecture of the composite film has a significant influence on thermal-tolerance and adhesive properties. This composite material has great application potential as a PSA (pressure sensitive adhesive). Our research demonstrates an excellent composite system and provides a convenient approach to realize a wide range of multifunctional fillers, compatible with processing on flexible polymer substrates.