Water model determines thermosensitive and physicochemical properties of poly(N-isopropylacrylamide) in molecular simulations

Poly ( N -isopropylacrylamide) (PNIPAM) is a famous representative of thermosensitive polymers. Thermosensitive polymers undergo phase transition with lower critical solution temperature. Commonly, their behavior linked to conformational collapse above certain This called Coil-Globule transition. In contrast, most other usually show inverse temperature behavior, i.e., an upper temperature, corresponding Globule-Coil Besides numerous possible applications, are interest for fundamental research, because similarities macromolecular transitions, e.g., protein folding. The counter-intuitive commonly associated solvation effects. Thus, accurate description the solvent crucial investigation in molecular simulations. Here, we investigate influence silico water model on dynamics To this end, performed extensive atomistic simulations syndiotactic PNIPAM 20-mer at multiple temperatures eight different models–four which 3-point models (TIP3P-type) and four 4-point (TIP4P-type). We found that strongly influenced by Depending model, ensemble polymer shifted significantly, leads dramatically results: estimated may span between 255 350 K. Consequently, depending solvent, physicochemical mechanical properties these polymers, polymer-solvent affinity persistence length, vary. These divergent results originate from strength interactions but also bulk state solvent. Both quantities vary models. Lennard-Jones interaction parameter ϵ correlates polymer. Indeed, quadrupole moment shows even higher correlation quantity. Our suggest connection diagram