title: Controlling volume shrinkage in soft lithography through heat-induced cross-linking of patterned nanofibers.
abstract: When poly(isopropylidene diallylmalonate) rich in threo-disyndiotactic sequences (st(rich)-2) was utilized as a cross-linkable ink for microcontact printing, the resultant submicrometer-scale patterns featuring 700 and 300 nm wide stripes were successfully insolubilized while maintaining their high dimensional integrity by heat-induced cross-linking with elimination of CO(2) and acetone. In sharp contrast, although the thermal properties and reactivities of a polymer rich in threo-diisotactic sequences (it(rich)-2) and a polymer having low stereoregularity (2(low)) are little different from those of st(rich)-2, the patterns printed with these reference polymers collapsed considerably upon heating as a result of a volume shrinkage effect. The striking difference between st(rich)-2 and the other two polymers most likely arises from the nanofiber-forming character of st(rich)-2, where the printed stripes are porous and much less affected by the volume shrinkage of individual nanofibers.
authors.affiliation: Department of Chemistry and Biotechnology, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
authors.forename: Yasunao
authors.initials: Y
authors.lastname: Miyamura
authors.forename: Chiyoung
authors.initials: C
authors.lastname: Park
authors.forename: Kazushi
authors.initials: K
authors.lastname: Kinbara
authors.forename: Frank A
authors.initials: FA
authors.lastname: Leibfarth
authors.forename: Craig J
authors.initials: CJ
authors.lastname: Hawker
authors.forename: Takuzo
authors.initials: T
authors.lastname: Aida