The Modification of Polyvinyl Alcohol for Ice Nucleation Based upon the Structures of Antifreeze Glycoproteins Found in Antarctic Fish

Abstract

Various alternative compounds have been investigated to prevent icing, one of which includes poly(vinyl) alcohol (PVA), which has shown promising anti-freeze effects. However, determining the optimal structures and formulations of PVA for anti-icing applications has remained a challenge. Building upon our previous work, which used molecular dynamics simulations to assess the effects of hydroxyl group separation distance on ice nucleation, in this work, PVA was modified based upon the structures of antifreeze glycoproteins (AFGPs) found in Antarctic fish, and examined as a potential antifreeze compound. Four different PVA samples with different degrees of hydrolysis were fabricated and subsequently examined for their effects on ice crystallization. The results showed that the modified PVA samples with degrees of hydrolysis of 76% and 66% had an effect on ice crystallization, delaying ice crystallization by an average of approximately 20 min, and even preventing ice crystallization altogether in a small portion of the sample. Meanwhile, other samples with degrees of hydrolysis of 100% and 34% either showed no effect on ice crystallization, shortened the ice crystallization time, and appeared to promote ice nucleation.

Moisture Adsorption–Desorption Behaviour in Nanocomposite Copolymer Films

“…From Figure 6 a, peaks (a, b and c) as assigned in the spectrum represent the repeating units of VAc, while peaks (d and e) proved the presence of AA repeating units in the copolymer [ 29 , 30 , 31 , 32 ]. The absence of sharp peaks (c and b) at around 1.9 and 4.8 ppm, respectively as well as the appearance of new signals ranging from 4.3–4.6 ppm (h–i) in Figure 6 b confirms that PVAc has converted into PVA.…”