Application of polymer nanoparticle coating for tuning the hydrophobicity of cellulosic substrates.

Nanoparticles of partially imidized poly(styrene-maleic anhydride) were applied from an aqueous dispersion as a one- or two-layer coating onto paper substrates, for controlling the paper surface hydrophobicity and improving the water barrier resistance. The effect of deposition conditions and thermal treatments on the topography and properties of the coating was studied by scanning electron microscopy, atomic force microscopy (AFM), contact angle measurements, and friction measurements. The wettability of paper surfaces with adsorbed nanoparticles can be controlled by tuning the chemical and topographical surface parameters: the water contact angles were found to increase at higher imide content as determined by Raman spectroscopy (depending on synthesis and thermal treatment), and higher average surface roughness determined by AFM (depending on the deposition method). The present technique may serve as a unique replacement for chemical treatments hydrophobizing fibrous substrates. [ABSTRACT FROM AUTHOR]