Layer-by-layer assembled nanoparticles: A novel method for surface modification of natural rubber latex film

The deposition of poly(methyl methacrylate) (PMMA) particles onto natural rubber (NR) latex film surface was successfully performed by the layer-by-layer (LbL) technique via electrostatic interaction. The charge on NR film was generated by UV grafting polyacrylamide (PAAm) onto the rubber surface pretreated with argon plasma. Attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy revealed that the grafted yield was directly proportional to the monomer concentration and to UV irradiation time. The contact angle measurement also confirmed the increase in hydrophilicity of the PAAm grafted NR (NR-g-PAAm) film surface. The presence of PMMA latex particles on the NR-g-PAAm sheet was clearly observed under scanning electron microscope (SEM). The percent surface coverage of PMMA particles on the substrate (Cs) depended on the latex concentration, immersion time, ionic strength and pH of medium. The increase in surface roughness, caused by the adsorbed latex particles, was confirmed by atomic force microscopy (AFM).