Polystyrene (PS, 1), polycaprolactone homopolymers (PCL, 2) and 3-Iodo-2-propynyl n-butylcarbamate (IPBC, 3) were physically mixed in dichloromethane (DCM) and processed into solid microspheres by using emulsion solvent evaporation method. Five different compositions with varying PS/PCL ratio were tested. The phase morphology of the microspheres was studied using Phase imaging atomic force microscopy (AFM) of polished cross-sections. Scanning electron microscopy was utilized to assess the distribution of IPBC in the polymer microspheres. The phase separation of the PS and PCL polymers in solvent cast films was assessed using polarized light optical microscopy of 11 polymer blends (0-100 wt-% PCL in PS). The PS/PCL-IPBC microspheres were incubated in water at RT and the release of IPBC was studied using high performance liquid chromatography (HPLC) at time points 1, 7 and 30 days. The microspheres dispersed in water borne outdoor paint matrix were tested for their antifouling activity against moulds in vitro.