Film Formation of Nano Sized hard Latex in Soft Polymer Matrix By Fluorescence Technique

This work reports steady state fluorescence (SSF) technique for studying film formation from pyrene (P)-labeled nano-sized polystyrene (P-PS) and poly(n-butyl acrylate) (PBA) hard/soft latex blends. Eight different films were prepared from mixtures of P-PS and PBA in dispersion and annealed at elevated temperatures above glass transition temperature of polystyrene for 10 min. Monomer (IP) and excimer (IE) intensities from P was measured after each annealing step to monitor the stages of film formation. The evolution of transparency of blend films was monitored using photon transmission intensity, Itr. Film morphologies were examined by atomic force microscopy (AFM). For 50-100%wt range of P-PS, two distinct film formation stages, which are named as void closure and interdiffusion were seen in (IE/IP) data. These stages were modeled and related activation energies were determined. There was no observable change in activation energies confirming that film formation behavior is not affected by varying the blend composition