Improving nanoparticle dispersion and polymer crystallinity in polyvinylidene fluoride/POSS coatings using tetrahydrofuran as co-solvent

Abstract

Dispersion quality of nanoparticles has always limited the performance of polymer nanocomposites and coatings. Herein, the main purpose is to improve the dispersion quality of nanoparticles and overall properties in polyvinylidene fluoride (PVDF)/polyhedral oligomeric silsesquioxane (POSS) nanocomposites fabricated through spray-coating technique. POSS was added to PVDF/DMF solution at varying concentrations. Based on morphological analysis, low to moderate contents (1 and 3 wt%) of POSS exhibited a good dispersion quality but the high contents (5 and 10 wt%) of POSS led to the formation of large aggregates. To improve the dispersion quality of POSS, tetrahydrofuran (THF) was used as co-solvent. The improved dispersion of POSS caused a significant enhancement in the crystallinity of PVDF from 29.8–59.5% according to the differential scanning calorimetry (DSC) results. X-ray diffraction results revealed that the majority of PVDF crystals from the α-type and addition of co-solvent led to the formation of a slight amount of γ phase which was confirmed by the multiple endotherms based on DSC results. The co-solvent addition also led to higher hydrophobicity due to the increased crystallinity. Overall, the use of a proper co-solvent led to better dispersion of nanoparticles which can result in improved performance of nanocomposite coatings.