Dipole-Driven Self Assembly in Polyzwitterion Solutions

Presenter

Pranav Krishna Viswanathan

Campus

UMass Amherst

Sponsor

Murugappan Muthukumar, Department of Polymer Science and Engineering, UMass Amherst

Schedule

Session 1, 10:30 AM - 11:15 AM [Schedule by Time][Poster Grid for Time/Location]

Location

Poster Board C30, Poster Showcase Room (163), Row 3 (C21-C30) [Poster Location Map]

Abstract

The self-assembly of charged macromolecules is a process that is ubiquitous in a wide variety of phenomena in the natural world, especially in biological systems. Typically, these self-assembly processes have been understood as a result of charge-charge interactions between oppositely charged macromolecules. As a paradigm shift, there is a growing recognition in the literature that dipole-dipole interactions play a significant role in self-assembly of macromolecules. Understanding the role of dipole-dipole interactions is still in its infancy. 

Polyzwitterions have been an ideal system for such a study. Through environmental and structural modification, we are able alter features such as dipole moment, dipole orientation, and domains of charge. In this work, we have synthesized a sulfobetaine-based polyzwitterion (pSBMA) and have characterized its phase behavior in water. We have observed that this polymer exhibits an upper-critical solution temperature behavior in water. Investigation using dynamic light scattering (DLS) of pSBMA shows both single chain structures and multi-chain aggregates, which are screened upon the addition of salt. 

Our current work is utilizing scattering techniques to probe the size and shape of the aggregates in response to changes in temperature and polymer/salt concentration. We are also investigating the critical phenomena of the pSBMA/water system. We suspect that the multi-chain aggregates will lead to a suppression of concentration fluctuations—leading to deviations from the 3D-Ising universality class. 

Understanding the phase behavior of these systems will provide insights into the phase behavior of other highly-dipolar polymers, like intrinsically disordered proteins (IDPs) and related diseases like Parkinson’s. 

Keywords

membraneless organelles, polyzwitterions, dipoles, liquid-liquid phase separation, mesomorphic state

Research Area

Chemistry and Materials Science

SIMILAR ABSTRACTS (BY KEYWORD)