Preparation and characterization of glassy plasma polymer membranes

  • J. Weichart
  • J. Müller
Conference paper
Part of the Progress in Colloid & Polymer Science book series (PROGCOLLOID, volume 85)


Plasma chemical vapor deposition of hexamethyldisilazane was investigated for its applicability as solubility controlled gas separation membranes. Substrates were porous inorganic membranes (Anotec: 0.02 µ) for permeation measurements and silicon wafers for deposition rate, density, and infrared measurements. To ensure a uniform membrane on the porous support a deposit of five times the pore diameter was required. Membranes deposited at 2.45 GHz from HMDSN/O2 mixtures exhibit a high deposition rate (1.8 nm · s−1) and a wide density range (1.15–1.60 g · cm−3). — Typical nitrogen permeation rate of a 100 nm film was 2 · 10−8 m3 (STP) s−1 m−2 Pa−1. Permeation rates of CO2 and C4H10 related to N2 and the thermal dependence indicate that the permeation is viscosity controlled. These films exhibit a microgel-like structure with an estimated pore diameter of 2 nm. Anodic films prepared in a 13.56 MHz parallel plate reactor at low deposition rate (0.3 nm · s−1) have densities between 1.3 and 1.5 g · cm−3. They exhibit an infrared absorption of the ·:CH3 vibration at ∼1260 cm−1, which is an easy accessible indication of crosslinking and oxidation of more than twice than in microwave plasma films. For an 0.6-µm anodic film an ideal separation factor for CO2/N2 and C4H10/N2 of ∼6 is obtained, which is comparable to that of 1-µm conventional polydimethylsiloxane.

Key words

Membrane plasma polymerization gas permeation silicone 


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Copyright information

© Dr. Dietrich Steinkopff Verlag GmbH & Co. KG 1991

Authors and Affiliations

  • J. Weichart
    • 1
  • J. Müller
    • 1
  1. 1.Technische Universität Hamburg-Harburg FSP 4-07HamburgFRG

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