Ice growth inhibition by poly(vinyl alcohol): Insights from near-infrared spectroscopy and molecular dynamics simulation

Poly(vinyl alcohol) (PVA) is a well-known ice recrystallization inhibitor, yet its antifreeze mechanism remains debated. Here, the mechanism of PVA is elucidated by means of near-infrared spectroscopy and molecular dynamics (MD) simulations. Analysis of the spectra of PVA solutions during the ice growth process reveals a dynamic interaction conversion from PVA-water to PVA-ice, indicating that PVA inhibits ice growth by directly binding to ice. Moreover, we observed OH binding to the ice surface through one or two hydrogen bonds but did not witness the previously reported formation of three hydrogen bonds when the OH group perfectly embeds into the ice crystal lattice. In addition, the spectral feature of CH2 groups of PVA indirectly indicates their significant contribution to inhibiting ice growth through hydrophobic interactions. The MD simulations further confirm the effective roles of both OH and CH2 groups for inhibiting ice growth.