Study of the chemical softness, chemical hardness, chemical stability and interaction energy of the piezoelectric composite: \(\left( { - {\text{CH}}_{2} - {\text{CF}}_{2} - } \right)_{3} /{\text{nHfO}}_{2}\)

This article aims to study the chemical reactivity of HfO₂-doped \(\left( { - {\text{CH}}_{2} - {\text{CF}}_{2} - } \right)_{3}\) (PVDF) in order to understand the aging process within it. For this purpose, properties such as chemical potential, chemical hardness and chemical flexibility and interaction energy are determined. Thus, we determined these properties for virgin PVDF, virgin HfO₂ and the doped PVDF molecule. We obtain through these article relevant results. The PVDF/HfO₂ molecule has a hardness greater (\(\eta\) = 2.95) than that of virgin PVDF (\(\eta\) = 1.29) and doubly or triply doped (\(\eta\) = 1.19, \(\eta\) = 0.64). This result implies higher chemical stability for the PVDF/HfO₂ molecule due to an interaction between a highest occupied molecular orbital (Homo) and a lowest occupied molecular orbital (Lumo) of stabilizing nature. Therefore, the PVDF/HfO₂ limits the charge transfer by opposing the electronic density distribution change or a reduction in the polarizability. However, in terms of flexibility, the PVDF/2HfO₂ and PVDF/3HfO₂ molecules, respectively, have a sweetness s = 0.84 and s = 1.56. This sufficiently demonstrates that the PVDF/3HfO₂ molecule is more flexible than the others. Finally, the advantage of this study is that we have obtained modified piezoelectric polymers which have new properties that are more valued with respect to their constituents. Our results show that doubly doped PVDF combines good flexibility and good hardness. This implies that this composite has good chemical stability compared to virgin PVDF. Therefore, the aging process is slow for this compound. In short, the doping of PVDF with HfO₂ is a good alternative to remedy the loss of activity within the PVDF.