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

The near-infrared spectra of PVA solutions during the ice growth process were presented, and the WPT method was employed to enhance spectral resolution. In the high-resolution spectra, two new peaks emerged at 6767 and 6661 cm−1, with their intensity increasing as the ice grows. These two peaks related to OH groups in PVA forming one and two hydrogen bonds with water molecules, respectively. Validation was conducted through MD simulations. [Display omitted] • NIR spectroscopy combined with MD simulations is use for studying the interactions between PVA and ice. • Wavelet Package Transform was used to enhance the resolution of the spectra. • OH groups of PVA bind to like-ice molecules through one or two hydrogen bond(s). • CH 2 groups play an important role in the ice-growth inhibition of PVA. • There is a collaborative effect between CH 2 and OH groups during the ice-growth inhibition of PVA. 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 CH 2 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 CH 2 groups for inhibiting ice growth. [ABSTRACT FROM AUTHOR]