Control of the three-dimensional periodicity of porous polymeric materials (PPMs) has enormous potential for photonics, separations and tissue engineering. Controlled pore sizes and porosity of PPMs have shown to be essential characteristics in all of these fields.¹ Our work is concerned with the fabrication of three-dimensionally periodic PPMs that have well-defined sections with different pore sizes using colloidal templating.

Colloids of different sizes are convectively assembled inside capillaries. A liquid polymer is used to fill the interstitial spaces formed by the colloidal assembly. Subsequently, the polymer is cured to form a solid colloid-polymer matrix. An inverse opal structure forms upon dissolution of the colloids from the matrix, leaving behind a multi-sectioned PPM. We have assembled 0.5, 2.4, and 9.6 µm sized sulfate-polystyrene (PS) colloids in 50 µm inner-diameter polymethylmethacrylate (PMMA) capillaries with various sequences. The hexagonally close-packed crystals formed have been infiltrated by a UV curable prepolymer, which has been cured subsequently under a long-wave UV light (365 nm). Treatment of the cured colloid-polymer matrix with organic solvents leads to porous polymeric materials with a controlled pore size distribution.

We have investigated the structure of colloidal assemblies and the resulting PPMs using scanning electron microscope and will present our findings. Further, knowledge of properties and characteristics of these PPMs are critical in practical applications, therefore, a preliminary tensile strength and UV-Vis analysis will be also presented.

(1) Xia, Y.N.; Gates, B.; Yin, Y.D.; Lu, Y.; Monodispersed colloidal spheres; Old materials with new applications. Advanced Materials 2000, 12, (10), 693-713.