"Dynamic stress-induced alterations in the physical and electrical properties of poly (vinyl alcohol) films via novel low-energy shock wave treatment"

Abstract

In this study, the polyvinyl alcohol (PVA) films were subjected to a continuous impact of a series of low-energy shock waves of supersonic speed having Mach number around 1.6 to 1.7. The PVA samples were exposed to a series of 50, 100 and 150 number of shock wave shots. The shock wave treated samples are subjected to physical, chemical and electrical property testing. The results of the characterization revealed that the unusual physical conditions resulting from the shock wave impact phenomenon could induce intriguing physicochemical effects beyond mere physical damage to the material. Specifically, we observed a 0.1 eV decrease in the energy gap of the PVA material and an increase in electrical conductivity from 8×10−5Scm−1 to 21 ×10−5Scm−1. Furthermore, a significant increase in the crystallinity of the amorphous PVA material was noted, with the degree of crystallinity rising from 12% to 35% after the shock wave treatment. Additionally, it was observed that the material's nature shifted from hydrophilic to hydrophobic. Consequently, the study suggests that the shock wave treatment method for material processing could offer a promising approach to tailor the physical and electrical properties of materials.