02034nas a2200157   4500008004100000022001400041245013800055210006900193260011000262300001400372490000600386520130800392100003001700700001501730856013101745       2013                        eng d  a1744-683X00aStructural and dynamical properties of polyethylenimine in explicit water at different protonation states: a molecular dynamics study0 aStructural and dynamical properties of polyethylenimine in expli  aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcJAN  a2269-22810 v93 a<p>PEI is a pH sensitive polymer which acts as a proton sponge in acidic conditions. Despite many experimental and theoretical efforts, a fundamental understanding of the structure and dynamics of linear PEI chains on the atomistic level at different protonation states in dilute solutions remains a topic of discussion. This report analyses the structural properties of PEI at different protonation states, which are representative of different pH, using all atomistic molecular dynamic simulations. The structural properties revealed that the polymer at high pH (basic medium) is highly coiled, while at low pH (strong acidic conditions) the chains are elongated. We studied the dynamics and ordering of water molecules that are part of the solvation shells of the PEI chains at different protonation states. We observe that the water molecules are ordered along the polymer backbone for a completely protonated PEI chain (i.e. in the case of acidic pH) and hop to the neighbouring solvation shell. The residence time and the self-diffusion of water molecules in the solvation shells and their activation barriers were also calculated and analysed further. We concluded the study by correlating the solvation shell water dynamics and the structure of the PEI chain at different protonation states.</p>1 aChoudhury, Chandan, Kumar1 aRoy, Sudip  uhttps://library.ncl.res.in/content/structural-and-dynamical-properties-polyethylenimine-explicit-water-different-protonation-0