Cross-Linked Random Copolymer Mats for Controlling the Orientation of Block Copolymers and their Supramolecules in Thin Films
Date Issued
2011
Date
2011
Author(s)
Lin, Xin-Guan
Abstract
A series of benzocyclobutene-functionalized random copolymers of styrene and 4-vinylpyridine were synthesized by nitroxide-mediated controlled radical polymerization with BPO and TEMPO.Our research was to use these random copolymers [P(S-r-BCBr-4VP)] to control the orientation of microdomains in thin films of poly(styrene-b-4-vinylpyridine) block copolymer (PS-b-P4VP) and their supramolecules based on an ultrathin cross-linkable film.
We used PS(20,000)-b-P4VP(17,000) and PS(48,000)-b-P4VP(20,300) two kinds of block copolymers which possess lamella and cylinder in bulk morphology, respectively. In particular compositions of random copolymer,we found that the parallel orientation of lamella is switched to be perpendicular in PS(20,000)-b-P4VP(17,000) thin film with the formation of islands and holes.In another system,the parallel orientation of cylinders is switched to be perpendicular in PS(48,000)-b-P4VP(20,300) thin film.These results revealed that the modifid substrate can successfully control the orientation of microdomains in thin films.Therefore,we investigated the effects of modifid substrate on supramolecular thin films.
On the P4VP-modified substrate, the surface morphology is dramatically changed.We found that the parallel and perpendicular orientation of cylinder is switched to be hexagonally perforated layer (HPL) and parallel orientation of cylinder,respectively.On the PS-modified substrate,we found that at the higher grafting density of PDP onto P4VP chains ,i.e x=0.8-1.5,the comb block lamellar orientation is switched to be perpendicular orientation of lamellae through the underlying thin film, nevertheless,the orientation of the large-scale cylinders were maintained.
Subjects
block copolymer
supramolecule
thin film
random copolymer
substrate modification
Type
thesis
File(s)![Thumbnail Image]()
Loading...
Name
ntu-100-R98549020-1.pdf
Size
23.54 KB
Format
Adobe PDF
Checksum
(MD5):d5558fe6e7db1ea6fe8015e9822a06b1