We present a detailed, large-scaled <i>ab initio</i> molecular dynamics investigation of the interfaces of calcium-silicate-hydrate (CSH) and a model polymer. This study identifies the bonding motifs between the polymer functional groups and cement’s surface binding sites, thereby explaining macroscopic observations by experiments and the self-healing mechanism between the polymer and cement. On stable (cured) CSH surfaces, the polymer only weakly adheres through coordination and weak hydrogen bonding interactions and can be easily mobilized. On fractured CSH surfaces, the polymer anchors through strong ionic Ca-O bonds resulting from deprotonation of polymer hydroxyl groups. The overall healing and elasticity properties of the composites very likely stems from a flexible hydrogen bonding network and ionic bonds that can be readily adapted to surface morphology. As a result, the S-S bridges remain intact and available to maintain the self-healing properties of the polymer. We identify spectroscopic signatures that can be used to confirm the proposed surface chemistry. Effects of water on the dynamics and adhesion of the polymer on CSH will also be discussed.

Understanding self-healing function in cement-polymer composites: <i>Ab initio</i> molecular dynamics simulations

254th National Meeting (2017)

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Understanding self-healing function in cement-polymer composites: Ab initio molecular dynamics simulations