Molecular Modeling of Polymer Membranes for Wastewater Cleanup

Jeff Errington Group and Haiqing Lin Group Collaboration for Molecular Modeling

Simulation snapshot (configuration) of a hydrated membrane consisting of a polysulfone base (colored gray) and a poly(ethylene glycol) diacrylate brush (blue, red and white spheres). Water molecules have been removed to maintain visibility of the polymer.

There is broad interest in developing membrane systems for handling wastewater from a diverse array of sources (e.g., household wastewater, drainfields). The ideal membrane permits pure water to permeate through and rejects contaminants. The permeated water is then reused, reducing the impact of the wastewater on the environment.

Overview

The Lin group is pursuing a promising class of polymeric membranes that consist of a polymer brush tethered to a base polymer structure (see image). Key design questions for these materials involve the types of polymers to use and how to tether them to the surface (e.g., grafting density, polymer length). Fundamental questions about the molecular-level organization of water and contaminants in the vicinity of the polymer brush must be addressed to fully understand the origins of membrane performance. The Errington group is now collaborating with the Lin group to address these questions via molecular simulation. The work is led by Yiqi Chen, a chemical engineering PhD student. The team has developed a framework for estimating interfacial properties (e.g., water contact angle) and has established metrics for characterizing how water organizes near the surface of these materials. Moving forward, the aim is to use the recently developed computational tools to accelerate the design and discovery of improved polymeric membranes for water treatment.