(552a) Asymmetric Membranes With Internal Active Domains

Despite the fast development of membranes, cost-effective, environmentally benign, and multi-functional design remains a challenge for next-generation materials. In this paper, we present a strategy combining extremely straightforward techniques for creating membranes with and highly adjustable properties (e.g. pore size, specific surface area, surface properties).  One of the unique characteristics of these membranes is that the active layer is actually contained within the supporting layer rather than as an external layer (which is typical for asymmetric membranes).  This structure is created by infiltrating a particle solution into the porous scaffold and then drying from one side of the membrane, such that evaporation pulls the particles to the open side. To create more complex structure, a two-step infiltration/drying process is used, in which microparticles and nanoparticles are infiltrated sequentially. The resulting active domains are of a thickness less than 1% of that of the membrane for micro-particles and even smaller for nanoparticles. This design is versatile as it works effectively with a large variety of particles, regardless of their size, shape, or material. Because of its compatibility with a large group of particles, this method is promising in building membranes with changing properties by infiltrating more than one type of particle.