A cationic macromonomer, 2-methacryloylethylhexadecyldimethylammonium bromide MA16, and a cationic macroinitiator, cationic acrylic/styrene oligomer end-capped with a nitroxide, were used to modify pristine Na−MMT, to enhance compatibility between the clay platelets and the host acrylic polymer matrix in waterborne nanocomposites. Both cationic species were successfully exchanged in the montmorillonite. The organically modified clays were used for the synthesis of acrylic (MMA/BA)/clay waterborne nanocomposites by miniemulsion polymerization. The 30% solids containing latexes were stable and coagulum free and presented better mechanical, thermal and barrier properties than the pristine acrylic copolymer.

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The use of sodium montmorillonite clay as a stabilizer in the surfactant-free emulsion polymerization of n-butyl acrylate/styrene (n-BA/S) was assessed. It was shown that the use of the clay alone did not yield the desired armored latex particles. A functional comonomer, that is, a phosphate ester of poly(ethylene glycol) monomethacrylate, was used to improve the interaction between the polymer and clay, thus allowing for the clay platelets to adhere to the surface of the polymer particles. The morphology of the films obtained for these two different scenarios was similar and resembled a honeycomb structure. However, their water-resistance properties differed drastically. The water absorption and water vapor permeation rate were much lower in the hybrid n-BA/S/clay films in the presence of the functional monomer than in the films obtained without the functional monomer.

a b s t r a c tThis study addresses the preparation and characterization of hybrid films prepared from Titanium dioxide (TiO 2 ) Pickering stabilized acrylic polymeric dispersion as well as their bacterial inactivation efficiency under sunlight irradiation. Complete bacterial inactivation under low intensity simulated solar light irradiation (55 mW/cm 2 ) was observed within 240 min for the films containing 10 weight based on monomers (wbm) % of TiO 2 , whereas 360 min were needed for the films containing 20 wbm% of TiO 2. The hybrid films showed repetitive Escherichia coli (E. coli) inactivation under light irradiation. TiO 2 released from the films surfaces was measured by inductively coupled plasma mass spectrometry (IPC-MS), obtaining values of ∼0.5 and 1 ppb/cm 2 for the films containing 10 wbm% and 20 wbm% of TiO 2 , respectively, far below the allowed cytotoxicity level for TiO 2 (200 ppb). Transmission electron microscopy (TEM) of the hybrid films showed that TiO 2 nanoparticles (NPs) were located at the polymer particle's surface forming a continuous inorganic network inside the film matrix. Atomic force microscopy (AFM) images showed differences in the TiO 2 dispersion between the air-film and film-substrate interfaces. Films containing 10 wbm% of TiO 2 had higher roughness (Rg) at both interfaces than the one containing 20 wbm% of TiO 2 inducing an increase in the bacterial adhesion as well as the bacterial inactivation kinetics. The highly oxidative OH• -radicals participating in the bacterial inactivation were determined by fluorescence.