Paper for Review: Nanoporous Parylene for Ultrafiltration

If you know me at all, you know I enjoy nothing more than ultrafiltration and Parylene-C deposition. Now these activities are combined into one device to improve the biocompatibility (platelet activation and adhesion) of nanoporous membranes.

In this letter, polyethersulfone (PES) membranes were coated with Parylene-C, poly(chloro-para-xylylene) aka (PCPX), while glycerin vapors rising through the pores kept the Parylene-C from forming over the pores, thus forming a nonoporous PCPX membrane. The claim of the letter is that by controlling the deposition thickness of the PCPX, enough pores are kept open and that diffusion actually increases due to the decrease in platelet activation and adhesion. The document is a little short on details, they don’t actually say what thickness of the polymer they are putting down, but the equipment manufacturer, Labcoater 2 (Specialty Coating Systems™, Indianapolis, Indiana) claims that pinhole free films of 25 nm are possible.

Prihandana_2012_Polyethersulfone Membrane Coated with Nanoporous Parylene for Ultrafiltration[1]

Figure 1: Parylene deposition on PES membrane porous assisted by glycerin
vapors.

Figure 2: SEM images of platelets adhering on diffusion channel. (a) PES
membrane. (b) PES membrane coated with parylene.

Enhancing the biocompatibility of PCPX  with plasma treatment has been explored [2]

[1]    G. S. Prihandana, H. Ito, Y. Nishinaka, Y. Kanno, and N. Miki, “Polyethersulfone membrane coated with nanoporous parylene for ultrafiltration,” Journal of Microelectromechanical Systems, vol. 21, pp. 1288-90, 12/ 2012.

[2]    S. Jeom Sik, L. Sukmin, J. Seong Hee, C. Gook Chan, and M. Mu Seong, “Improved biocompatibility of parylene-C films prepared by chemical vapor deposition and the subsequent plasma treatment,” Journal of Applied Polymer Science, vol. 112, pp. 3677-85, 06/15 2009.