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Weizhong Zou

Contact Information
Email weizhong@umich.edu
Phone 734.936.1381
Office 010 G047 NCRC, Biointerfaces Institute
University of Michigan, Ann Arbor, MI 48109
Education
B. S. Petroleum Engineering, China University of Petroleum, Beijing (2011).
M. S. Chemical Engineering, University of Michigan, Ann Abor, U.S. (2013).
   
Current Research

Wormlike Micelle Characterization

Surfactant or soap molecules, which are molecules with a water-loving "head" and an oil-loving "tail," self-assemble in water into a variety of aggregate structures called "micelles", and are at the center of many applications. While much is known about their physicochemical properties and flow behaviors (represented by G' and G" curvatures in the left part of the following figure), the complex dependencies of micelle structures (determined by the sponetaneous curvature, cpp in the right part of the figure below) on various types and concentrations of surfactant, salt, and additives (for instance, linalool, limonene, vanillin) make such solutions difficult to characterize and design for different applications.

Design

We have developed a fast "pointer" simulation method for the rheology of entangled micelles. Our method not only includes advanced relaxation mechanism from modern tube theories (i.e., reptation, contour length fluctuation, etc) but also uses "pointers" that track the ends of unrelaxed regions along each micelle, thereby allowing extractions of multiple micellar characteristic lengths and the complex dependencies of micelle structures (determined by the sponetaneous curvature, cpp in the right part of the figure below) on various types and concentrations of surfactant, salt, and additives time constants by fitting experimental rheology data across the entire available frequency range on commercial surfactant solutions. This simulation model is now used by Procter & Gamble scientists to help them understand and enventually design improved shampoo formulations.

PA

 

Dynamics of polymeric glass

Although the ability to form a glass is not restricted to a specific class of atoms or molecules, polymers can be easily cooled to form glasses with high impact resistence and toughness which makes them widely used in the manufacturing. We developed a hybrid model for polymeric glass under deformation that combines a minimal model of segmental dynamics with a beads-and-springs model of a polymer, solved by Brownian dynamics simulations. Based on this model, we were able to successfully capture the entire range of mechanical response for a typical polymeric glass under uniaxial extension including the observed yielding, plastic flow, strain-hardening, and incomplete strain recovery.

Polymeric Glass

 

Web

https://www.linkedin.com/in/weizhong-zou-463070ba