The innovation engine for new materials

Daniela Rivera Mirabal

Daniela Rivera Mirabal


Chemical Engineering


University of Puerto Rico at Mayagüez


Sally Jiao

Faculty Sponsor(s): 

Scott Shell

Faculty Sponsor's Department(s): 

Chemical Engineering

Project Title: 

Molecular dynamics simulations of polypeptoids reveal the effects of chemistry and topology on local water behavior

Project Description: 

Water structure, dynamics, and thermodynamics near surfaces influences the performance of a wide range of engineered systems, spanning water-filtration membranes, catalysis, and protein engineering. Previous computational work with idealized surfaces has shown that modifying and rearranging the chemical functionalities at the surface can impact water structure and dynamics; however, the surfaces studied are often challenging to replicate experimentally. Here, we realize spatially-controlled chemical heterogenities using polypeptoids, a class of polymers that can be synthesized sequence-specifically, using molecular dynamics simulations to probe the effects of heterogeneities encoded in the sequence on local water behavior. Specifically, we observe how the polypeptoid hydration water’s translational, orientational, and hydrogen-bonding structure and dynamics respond to changes in the number and location of hydrophobic and hydrophilic monomers. We furthermore investigate the independent effect of topology on water behavior by comparing conformations with the same sequence. Preliminary results suggest that hydrophobic monomers induce dehydration and dampen the dynamics of water near the polypeptoids, while collapsed conformations of a fully hydrophilic polypeptoid exhibit similar effects.