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I-N transition

I-N transition. Size distribution. c. Size (nm). Phase Transitions in Colloidal Suspensions of Disks Zhengdong Cheng, Texas Engineering Experiment Station, DMR 1006870.

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I-N transition

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  1. I-N transition Size distribution c Size (nm) Phase Transitions in Colloidal Suspensions of DisksZhengdong Cheng, Texas Engineering Experiment Station, DMR 1006870 Despite their natural abundance and wide industrial applications, such as red blood cells and clay, disks are the least studied colloidal systems compared to geometries like spheres and rods. We established methods to fabricate and control the size, aspect ratio, and polydispersity of disks. We systematically investigate their effects on discotic liquid crystal phase transitions. We found a power-law scaling for the onset of the I-N transition with aspect ratio. By tailoring inter-disk interactions, we also observed gelation of high aspect ratio nanoplates at low volume fraction. Comprehensive understanding of the colloidal discotics in terms of complex fluids behaviors and liquid crystal transitions will help establish theory for model atomic liquid crystals and develop industrial applications. a Disks & liquid crystals. (a) Fabrication: surface control of low aspect ratio wax disks. (b) Poly-dispersity-dependent phase transition of high aspect ratio a-ZrP disks. (c) Dependence of I-N transition on aspect ratio. (d) Gelled phases (IG & NG) of charged disk suspensions. b d A. Mejia et al. "Surface-controlled shape design of discotic micro-particles", Soft Matter, 6 (2010) 4885. f

  2. Phase Transitions in Colloidal Suspensions of DisksZhengdong Cheng, Texas Engineering Experiment Station, DMR 1006870 Education: This research project has involved three graduate students (one hispanic student A.F. Mejia, two female students Y. Chang and M. Shuai), five undergraduate students from TAMU (P. Nguyen, R. Ng, M. Simonnetty, S. Greer, and E. Risinger), one summer REU student, (X. Zhang, Univ. Michigan) and two high school students (C. Xie and A. Gawande). Outreach: The PI was invited by the Guangdong University of Engineering in China to lecture on “Colloidal crystals and liquid crystals”. The PI was invited to Mary Kay O’Connor Process Safety Center Steering Committee meeting to deliver talk “Nanoplates for industrial applications” to industrial safety leaders. Collaborations have been established with scientists in Spain and China. (a) (b) (c) Educational outreach. (a) Under graduate students R. Ng and M. Simonnetty discuss measurements. (b) High school student C. Xie performs experiment with R. Ng. (c) Xie is observing a sample with graduate student M. Shuai.

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