AVS 56th International Symposium & Exhibition
    Thin Film Wednesday Sessions
       Session TF-WeA

Paper TF-WeA12
Nanoscale Engineering of Ceramic Supports for High Permeance Ultrafiltration Membranes

Wednesday, November 11, 2009, 5:40 pm, Room B4

Session: ALD/CVD: Novel Applications, Mechanical Properties
Presenter: R. Nahm, Colorado School of Mines
Authors: R. Nahm, Colorado School of Mines
P.C. Rowlette, Colorado School of Mines
C.A. Wolden, Colorado School of Mines
Correspondent: Click to Email
Anodized aluminum oxide (AAO) membranes are commercially available supports that offer a high pore density and a narrow pore size distribution. In this talk, we describe the use of pulsed plasma-enhanced chemical vapor deposition (PECVD) to modify AAO supports for arbitrarily designed molecular weight size cutoffs. Pulsed PECVD is a self-limiting deposition technique that provides digital control over the amount of deposited material (i.e. 1 Å/pulse). Specifically, we use pulsed PECVD to deposit SiO2 at room temperature to affect arbitrary pore size control. For this work, pulsed PECVD is operated in a nonconformal mode, meaning that only the very pore opening is modified with no deposition occurring throughout the majority of the structure. Modified membranes are characterized by atomic force and electron microscopies. An advantage of this approach is that the modifications can be done very quickly. In addition, we demonstrate that the nominal pore size may be significantly reduced without any impact on the permeance. Moreover, these membranes provide a well-defined geometry that provides a unique experimental platform for studying hindered transport and nanofluidics. The modified membranes are characterized by gas permeance, water permeance, and measurements of solute rejection. SiO2 is the material of choice since it may be readily modified through addition of self-assembled monolayers to control the hydrophilicity of the surface and enhance biocompatibility. We will present preliminary work in this regard as well.