title: Physical Continuity and Vertical Alignment of Block Copolymer Domains by Kinetically Controlled Electrospray Deposition.
abstract: The fabrication of block copolymer (BCP) thin films is reported with vertically aligned cylindrical domains using continuous electrospray deposition onto bare wafer surfaces. The out-of-plane orientation of hexagonally packed styrene cylinders is achieved in the "fast-wet" deposition regime in which rapid evaporation of the solvent in deposited droplets of polymer solution drives the vertical alignment of the self-assembled structure. Thermally activated crosslinking of the polybutadiene matrix provides kinetic control of the morphology, freezing the vertical alignment and preventing relaxation of the system to its preferred parallel orientation on the nontreated substrate. Physically continuous vertically oriented domains can be achieved over several micrometers of film thickness. The ability of electrospray deposition to fabricate well-ordered and aligned BCP films on nontreated substrates, the low amount of material used relative to spin-coating, and the continuous nature of the deposition may open up new opportunities for BCP thin films.
authors.affiliation: Department of Chemical Engineering, Yale University, New Haven, CT, 06511, USA.
authors.forename: Hanqiong
authors.initials: H
authors.lastname: Hu
authors.affiliation: Department of Chemical Engineering, Yale University, New Haven, CT, 06511, USA.
authors.forename: Youngwoo
authors.initials: Y
authors.lastname: Choo
authors.affiliation: Department of Chemical Engineering, Yale University, New Haven, CT, 06511, USA.
authors.forename: Xunda
authors.initials: X
authors.lastname: Feng
authors.affiliation: Department of Chemical Engineering, Yale University, New Haven, CT, 06511, USA.
authors.forename: Chinedum O
authors.initials: CO
authors.lastname: Osuji
mesh_terms: D000096:Acetone; D002070:Butadienes / Q000737:chemistry*; D002725:Chloroform; D003460:Crystallization; D020724:Elastomers / Q000737:chemistry*; D055664:Electrochemical Techniques; D007700:Kinetics; D008422:Materials Testing; D008567:Membranes, Artificial; D049329:Nanostructures / Q000737:chemistry / Q000648:ultrastructure*; D010316:Particle Size; D011137:Polystyrenes / Q000737:chemistry*; D012997:Solvents; D013499:Surface Properties; D014050:Toluene
chemical_list: D002070:Butadienes; D020724:Elastomers; D008567:Membranes, Artificial; D011137:Polystyrenes; D012997:Solvents; D000096:Acetone; D014050:Toluene; D002725:Chloroform; C028834:polybutadiene
keywords: block copolymers; directed self-assembly; electrospray deposition; thin films