the wagner group















Kate Gurnon


Curriculum Vitae
B.S. Chemical Engineering, 2009
Worcester Polytechnic Institute, Worcester, MA

office: 042 Colburn Lab
email: akgurnon@udel.edu
phone: 302-831-6738

Shear thickening fluids for application in field responsive composite materials
Co-advised by Dr. Jack Gillespie

Concentrated near hard-sphere colloidal suspensions, or shear thickening fluids (STFs), have been shown to improve the ballistic protection of Kevlar (http://www.ccm.udel.edu/STF/index.html), the stab protection of fabrics [1] and have the potential to be incorporated in countless other applications such as the composite materials used for armored vehicles and protective sports equipment. As a field responsive material, STFs exhibit a reversible transition from a shear thinning to a shear thickening response with increasing applied shear stress [2]. During simple steady shear the shear thickening response is known to be connected with flow-induced microstructural rearrangements comprised of density fluctuations of particles in the suspension (termed “hydroclusters”) [2].For all of these applications it is important to understand STFs under dynamic conditions. The goal of the present research is to define the dynamic response of a model STF and to gain an understanding for the associated microstructural rearrangements in order to fully appreciate the origins of the shear thickening phenomena during dynamic deformations.

A combination of rheometry techniques and small angle neutron scattering (SANS) methods are used to better understand the shear thickening phenomena. As a result, the intimate connection between a concentrated colloidal suspension’s microstructural rearrangements and the resulting mechanical properties of the bulk material will be realized. The subsequent microstructure-property relationship will aid in the development of a model for colloidal suspensions that can be used to predict STF responses ultimately resulting in the rational design of STF composite materials for specific applications.

[1] D. Kalman and N. J. Wagner (2009). “Microstructure of shear-thickening concentrated suspensions determined by flow-USANS”, Rheol Acta 48: 897-908.
[2] N. J. Wagner and J. F. Brady (2009). “Shear thickening in colloidal dispersions.” Physics Today 62(10): 27-32.