Paper Number
PO47 

Session
Poster Session

Title
Aging and jamming behavior in model soft colloidal system

Presentation Date and Time
October 14, 2015 (Wednesday) 6:05

Track / Room
Poster Session / Atrium/Harborview

Authors (Click on name to view author profile)

1. Li, Qi (Texas Tech University, Chemical Engineereing)
2. Peng, Xiaoguang (Texas Tech University, Department of Chemical Engineering)
3. McKenna, Gregory B. (Texas Tech University, Chemical Engineering)

Author and Affiliation Lines (in printed abstract book)
Qi Li, Xiaoguang Peng, and Gregory B. McKenna
Chemical Engineereing, Texas Tech University, Lubbcok, TX 79409

Speaker / Presenter 
Li, Qi

Text of Abstract
Aging behaviors and structural recovery for the PS-PNIPAM/AA colloidal system are investigated in our experiments by using diffusing wave spectroscopy (DWS). The experimental sample for this research is a core-shell PS-PNIPAM/AA thermosensitive dispersion, with a degree of polydispersity of 25%, determined by dynamic light scattering (Nanotrac 250), to prevent the sample from crystallization. The sample is from the same batch as previous works from our group [1-3]. The sample concentrations range from 13.2 wt% to 16 wt%. A complete temperature dependence and a concentration dependence of the a-relaxation dynamics for our colloidal system is obtained. Jamming behaviors were discovered at lower temperatures for different mass concentration samples. The classic Vogel-Fulcher-Tammann (VFT) model of glass forming system is applied. The results deviate drastically from the classic model and the super-Arrhenius signature disappears below the glass transition temperature. A further comparison of the microscopic rheology and macroscopic rheology was made in our research.

[1] X. Di, K. Z. Win, G. B. McKenna, T. Narita, F. Lequeux, S. R. Pullela, and Z. Cheng, Phys. Rev. Lett.106, 095701 (2011). [2] X. Di, X. Peng, and G. B. McKenna, J. Chem. Phys.140, 054903 (2014). [3] X. Peng, and G. B. McKenna, Phys. Rev. E90, 050301 (2014).