The innovation engine for new materials

Kevin Curtis

Kevin Curtis, Chemical Engineering, University of California, Berkeley

Major: 

Chemical Engineering

University: 

University of California, Berkeley

Mentor(s): 

Mikayla Barry

Faculty Sponsor(s): 

Rachel Segalman

Faculty Sponsor's Department(s): 

Chemical Engineering

Project Title: 

Studying Water Dynamics at Peptoid-Water Interfaces

Project Description: 

To design energy-efficient membranes for water purification, water dynamics at polymer interfaces need to be understood and quantified. In order to better understand these interactions, we investigated the effects of hydrophobicity on water diffusion near polymer surfaces with biomimetic sequence-defined side chains known as peptoids. The Segalman Group has already quantified water diffusivity at short-chain, free floating peptoid surfaces through incorporating a NMR-active “spin label” group into the peptoid chain and examining the solution through ODNP (Overhauser Dynamic Nuclear Polarization) spectroscopy. Now we have decided to investigate the behavior of water near a polymeric membrane-like surface. For this, we used micelles containing a polystyrene core and a poly(ethylene oxide)-like segment with our peptoids anchored for ODNP analysis. By varying the location of spin labels in our peptoid sequences, we will be able to measure water diffusivity at several different distances from hydrophobic groups. We hypothesize that water diffusivity increases near hydrophobic surfaces, due to the fact that water has little attraction to these surfaces. In addition, we believe that this effect will only be present within a few nanometers of the hydrophobic side chains causing them. This will lead us to believe that designing membranes with regions of hydrophobic surfaces could increase water molecules movement through the membranes and will advance our fundamental knowledge of water-polymer interactions.