Preparation of stimuli-responsive functionalized latex Nanoparticles with various glass transition temperature

Functionalized latex nanoparticles containing spiropyran were prepared to investigate the effects of glass transition temperature (Tg) on the optical properties of photochromic materials. Samples were prepared via semi-continuous emulsion polymerization of methyl methacrylate (MMA) and butyl acrylate (BA) with different ratios and a constant amount of spiropyran ethyl acrylate (SPEA). The obtained particles were characterized by TEM analysis. The corresponding glass transition temperatures were measured by differential scanning calorimetry (DSC) and optical properties were studied by UV-Vis spectroscopy. It was found that by increasing Tg of the polymer chains, rate of isomerization (spiropyran to merocyanine) is enhanced under Uv irradiation at 365 nm.