From Hansen solubility parameters to new anti-icing, viscoelastic sponges of terpolymer of tetrafluoroethylene, vinylidenefluoride, and hexafluoropropylene (THV)

Abstract

THV, a relatively new hydrophobic polymer, has found wide application from explosives to sensors. Therefore, we decided to determine its Hansen Solubility Parameters (HSP) – one of the most important parameters in polymers processing. Studied 41 liquids can be divided into four groups: very good solvents (1), causing gelation (2) causing soaking or color change (3), and inert (4) and HSP values were calculated. We also proposed green chemistry solvents for THV. At the next stage, two solvents from group 1, and two from group 2, and their mixtures, were selected to determine the effect of a solvent on the THV sponge properties. The sponges were characterized by total pore volumes, porosity, mechanical properties, and surface morphology. Moreover, thermal, and anti-icing properties were studied for different film thicknesses. This holistic approach, together with a theoretical description of the icing process via a dynamic growth angle model, makes it possible to relate the sponge morphology to thermal, mechanical, hydrophobic, and anti-icing properties, showing that the studied sponges are strongly hydrophobic or superhydrophobic with a water contact angle (WCA) as large as 160° for THVAC. Considering anti-icing properties, total freezing time, delaying of recalescence, and possible ice removal by wind or vibration, the sponge obtained from the mixture of DMF and acetone (THVDMFAC) seems to be optimal. This sponge has the highest Young’s modulus, high thermal stability, and anti-freezing properties thus, it can be successfully applied in anti-icing covers in, for example, wind turbine blades.