title: Development of flexible LEO-resistant PI films for space applications using a self-healing mechanism by surface-directed phase separation of block copolymers.
abstract: Polimide-block-polydimethylsiloxane (PI-b-PDMS) block copolymers have been synthesized from commercially available amino-terminated polysiloxanes with different molecular weights, for use as polymeric materials resistant to the low earth orbit (LEO) space environment. A structural optimization with respect to maximum environmental protection has been performed by varying the PDMS block length as well as the architecture of the block copolymers spanning from multiblock to triblock and star-shaped morphologies. The synthesized polymers and casted films show good mechanical and thermal performance. For block copolymers with a load of 2% PDMS (in the case of the multiblock copolymers), a complete surface coverage of the PDMS has been found. It has been shown that the transfer of the surface enriched PDMS layer into a thin silica layer after atomic oxygen (AO) exposure results in a drastic decrease in AO erosion rate. The silica layer protects the underlying material from oxygen initiated erosion resulting in a drastic decrease of surface roughness. This phenomena is observable for loads as small as 6 wt % PDMS.
authors.affiliation: TNO Science and Technology, P.O. Box 6235, 5600 HE Eindhoven, The Netherlands. hartmut.fischer@tno.nl
authors.forename: Hartmut R
authors.initials: HR
authors.lastname: Fischer
authors.forename: Karin
authors.initials: K
authors.lastname: Tempelaars
authors.forename: Aat
authors.initials: A
authors.lastname: Kerpershoek
authors.forename: Theo
authors.initials: T
authors.lastname: Dingemans
authors.forename: M
authors.initials: M
authors.lastname: Iqbal
authors.forename: Henk van
authors.initials: Hv
authors.lastname: Lonkhuyzen
authors.forename: Boris
authors.initials: B
authors.lastname: Iwanowsky
authors.forename: Christopher
authors.initials: C
authors.lastname: Semprimoschnig
mesh_terms: D004129:Dimethylpolysiloxanes / Q000737:chemistry*; D006813:Humidity; D009757:Nylons / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry*; D012993:Solar Energy; D013026:Space Flight; D013314:Stress, Mechanical; D013499:Surface Properties; D013696:Temperature
chemical_list: D004129:Dimethylpolysiloxanes; D009757:Nylons; C085707:poly(dimethylsiloxane)-polyamide copolymer; D010100:Oxygen