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Lubricating effect of thin films of styrene-dimethylsiloxane block copolymers

Ndoni, Sokol; Jannasch, Patric LU ; Larsen, Niels B and Almdal, Kristoffer (1999) In Langmuir 15(11). p.3859-3865
Abstract
The lubricating effect of styrene-dimethylsiloxane block copolymer films spin cast on Si wafers was found to increase with increasing size of the poly(dimethylsiloxane) (PDMS) block. Friction properties of symmetrical and close-to-symmetrical block copolymers were evaluated in contact with bromobutyl rubber in a plate-on-plate configuration. X-ray photoelectron spectroscopy showed that the copolymer films were all covered by an at least a 10 nm thick layer of PDMS. The lubricating effect remained constant down to a film thickness comparable to the chain dimensions of the copolymer, R-0, after which it decreased progressively. At thicknesses below R-0, the copolymer dewetted the wafer and formed discrete domains with sizes comparable to... (More)
The lubricating effect of styrene-dimethylsiloxane block copolymer films spin cast on Si wafers was found to increase with increasing size of the poly(dimethylsiloxane) (PDMS) block. Friction properties of symmetrical and close-to-symmetrical block copolymers were evaluated in contact with bromobutyl rubber in a plate-on-plate configuration. X-ray photoelectron spectroscopy showed that the copolymer films were all covered by an at least a 10 nm thick layer of PDMS. The lubricating effect remained constant down to a film thickness comparable to the chain dimensions of the copolymer, R-0, after which it decreased progressively. At thicknesses below R-0, the copolymer dewetted the wafer and formed discrete domains with sizes comparable to R-0. The copolymer could further be blended with up to 70 wt % polystyrene without detecting a decrease in the lubricating effect. A mechanism is proposed for the observed frictional behavior where microflakes are abraded from lamellar copolymer surfaces and stick to the contacting rubber surface, whereafter lubrication may result from sliding of PDMS brushes against each other. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Langmuir
volume
15
issue
11
pages
3859 - 3865
publisher
The American Chemical Society
external identifiers
  • scopus:0032629281
ISSN
0743-7463
DOI
10.1021/la980986e
language
English
LU publication?
yes
id
010544b8-e083-4d74-afc6-a8452d9333b4 (old id 149899)
date added to LUP
2007-07-13 14:50:59
date last changed
2017-01-01 04:43:57
@article{010544b8-e083-4d74-afc6-a8452d9333b4,
  abstract     = {The lubricating effect of styrene-dimethylsiloxane block copolymer films spin cast on Si wafers was found to increase with increasing size of the poly(dimethylsiloxane) (PDMS) block. Friction properties of symmetrical and close-to-symmetrical block copolymers were evaluated in contact with bromobutyl rubber in a plate-on-plate configuration. X-ray photoelectron spectroscopy showed that the copolymer films were all covered by an at least a 10 nm thick layer of PDMS. The lubricating effect remained constant down to a film thickness comparable to the chain dimensions of the copolymer, R-0, after which it decreased progressively. At thicknesses below R-0, the copolymer dewetted the wafer and formed discrete domains with sizes comparable to R-0. The copolymer could further be blended with up to 70 wt % polystyrene without detecting a decrease in the lubricating effect. A mechanism is proposed for the observed frictional behavior where microflakes are abraded from lamellar copolymer surfaces and stick to the contacting rubber surface, whereafter lubrication may result from sliding of PDMS brushes against each other.},
  author       = {Ndoni, Sokol and Jannasch, Patric and Larsen, Niels B and Almdal, Kristoffer},
  issn         = {0743-7463},
  language     = {eng},
  number       = {11},
  pages        = {3859--3865},
  publisher    = {The American Chemical Society},
  series       = {Langmuir},
  title        = {Lubricating effect of thin films of styrene-dimethylsiloxane block copolymers},
  url          = {http://dx.doi.org/10.1021/la980986e},
  volume       = {15},
  year         = {1999},
}