Synthesis of Optically Complex, Porous, and Anisometric Polymeric Microparticles by Templating from Liquid Crystalline Droplets

Date

2016-10-25

Author

Wang, Xiaoguang
Büküşoğlu, Emre
Miller, Daniel S
Pantoja, Marco A. Bedolla
Xiang, Jie
Lavrentovich, Oleg D
Abbott, Nicholas L

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It is demonstrated that aqueous dispersions of micrometer-sized liquid crystal (LC) droplets provide the basis of a general and facile methodology for the templated synthesis of spherical and nonspherical polymeric micro-particles with complex internal structure and porosity. Specifically, nematic droplets of reactive (RM257)/nonreactive mesogens with distinct internal configurations are prepared using a range of approaches, the reactive mesogens are photopolymerized, and then the nonreactive mesogens are extracted to yield polymeric particles. It is found that LC droplets exhibiting bipolar, radial, axial or preradial configurations template the formation of spindle-shaped, spherical, spherocylindrical or tear-shaped polymeric microparticles, respectively. Each type of microparticle exhibits distinct optical signatures indicating the presence of an internal LC-templated, anisotropic polymer network. In addition, by using a microfluidic system to generate monodisperse LC droplets containing 10%-40% wt/wt of RM257, spindle-shaped microparticles with tailored aspect ratios ranging from 2.4 to 1.2 are formed. The mass density of spherical microparticles templated from radial LC droplets can be tuned to range from 0.2 to 0.6 g cm(-3), revealing the introduction of porosity (confirmed by electron microscopy) with a volume-average pore diameter of 39 +/- 16 nm (obtained from nitrogen sorption isotherms).

Subject Keywords

Electrochemistry, Electronic, Optical and Magnetic Materials, Condensed Matter Physics, Biomaterials

URI

https://hdl.handle.net/11511/37144

Collections

Department of Chemical Engineering, Article