Fig. 2: MD simulation of PVA swelling in water solution.

a Snapshot of swollen PVA. The water molecules are visualized as a cyan transparent surface. The cross-section size of those models is 4 nm × 4 nm, and the length of those models ranges from 24.0 nm to 24.4 nm. b Density profile of PVA and water. c Swelling dynamic. The left part is the result within 1000 ns, and the right part is the result adopt the proposal for accelerating the swelling process. The error bars are present SD of the DS values for the last five annealing cycle. d The HB number between PVA chains. e The HB number between PVA chains and water molecules. f PSD of swollen PVA. The scatter points of simulated PSD are fitted by the Gaussian function. g Visualization of pores with various degrees of cross-linking. The colors denotes the size of pore radius. Light yellow represents the minimum value (0.3 nm) and dark blue represents the maximum value (2.0 nm). h PSD with various degrees of cross-linking. The scatter points of simulated PSD are fitted by the Gaussian function. i DS with various degrees of cross-linking. The error bars are present SD of the DS values for the last five annealing cycle. The temperature is 300 K for all simulations. In Fig. 2cde, the lines in these figures serve as visual guide.