279057 Temperature-Responsive Nematic Hydrogels

Thursday, November 1, 2012: 3:20 PM
413 (Convention Center )
Andres F. Mejia1, Ratna Ng1, Peter Nguyen1, Hugo Y. Acosta1, M. Sam Mannan2 and Zhengdong Cheng1, (1)Chemical Engineering, Texas A&M University, College Station, TX, (2)Mary Kay O'Connor Process Safety Center, Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX

We report the fabrication of temperature-responsive nematic hydrogels using large aspect ratio (ξ = diameter/thickness) zirconium phosphate (ZrP) monolayers embedded into a polymer network. To achieve an ordered nanostructure, these monolayers were immersed into a monomer solution. The monolayer suspension was macroscopically oriented by shear flow and polymerized in situ to obtain a nematic hydrogel. The alignment of the large aspect ratio nano-sheets by a weak external stimulus enables the formation of nematic textures during hydrogel formation. Cross-polarizing micrographs revealed the liquid crystallinity of the nematic hydrogels. We analyzed the influence of the initiator and the catalyst on the nematic textures. Furthermore, by setting the temperature above 32ºC, we found that the nematic hydrogel experienced volume shrinking evolving the variation of the nematic textures. Finally, at low monolayer concentrations the hydrogels presented an isotropic-nematic (I-N) order transition on the edge. The nematic hydrogels synthesized in this work open new perspectives for technological applications of these systems to optical devices.

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See more of this Session: Colloidal Assembly and Device Fabrication
See more of this Group/Topical: Engineering Sciences and Fundamentals