Drying and thermal studies of antimicrobial – poly(styrene)-poly(methyl methacrylate)-toluene coatings doped with CuO nanoparticles

Abstract This study explores the drying behavior, residual solvent content, and thermal properties of antimicrobial poly (styrene)-poly (methyl methacrylate)-toluene (PS-PMMA-TOL) coatings incorporated with CuO nanoparticles. The inclusion of CuO nanoparticles significantly enhances the thermal stability and mechanical properties of the coatings while reducing residual solvent content. Four different coating systems were analyzed, varying the mass percentages of PS, PMMA, CuO, and toluene. Key findings include a substantial reduction in residual solvent content, with Coating 1 exhibiting the lowest solvent retention at 2.96 %, and Coating 4 retaining up to 5.44 %. This decrease is attributed to the enhanced diffusion and increased free volume within the polymer matrix. Additionally, a two-stage drying process was observed, consisting of an initial rapid evaporation phase followed by a diffusion-controlled period. The inclusion of CuO nanoparticles also elevated the glass transition temperature (T g ) of the coatings, with Coating 1 showing the highest T g of 78.07 °C, enhancing rigidity and thermal stability. Higher polymer content, particularly in Coatings 3 and 4, led to thicker films with higher residual solvent retention, affecting flexibility and mechanical performance. These findings provide valuable insights into the development of high-performance antimicrobial coatings, with potential exploration into eco-friendly solvent alternatives for sustainable and efficient coating solutions.