Excluded volume tunes water diffusivity near non-polar surfaces

Water behavior near soft interfaces plays a central role in a wide range of applications from drug delivery and catalysis to sensing and water purification. While well established that water thermodynamics facilitate surface-solute interactions critical to soft material performance, controlling water behavior in systems in which functionalities can be flexibly incorporated remains a longstanding challenge. This work uses versatile sequence-defined polypeptoids to demonstrate that water behavior can be tuned near polymeric surfaces. This system simultaneously offers both a route to control functional group position and a unique opportunity to map water diffusivity moving away from a surface with Overhauser dynamic nuclear polarization. Our results demonstrate that excluded volume causes water dynamics to slow in proximity to non-hydrogen bonding surfaces – an important consideration in the design of functional soft materials.