Browsing by Author "Hsieh, Chih-Yi"

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Characterization of patterned poly(methyl methacrylate) brushes under various structures upon solvent immersion
(2009-10-15)
Chen, Jem-Kun
;
Hsieh, Chih-Yi
;
Huang, Chih-Feng
;
Li, Po-min
;
應用化學系
In this paper we describe a graft polymerization/solvent immersion method for generating various patterns of polymer brushes. We used a very-large-scale integration (VLSI) process and oxygen plasma system to generate well-defined patterns of polymerized methyl methacrylate (MMA) on patterned Si(1 0 0) surfaces through atom transfer radical polymerization (ATRP). After immersion of wafers presenting lines of these PMMA brushes in water and tetrahydrofuran, we observed mushroom-and brush-like regimes through grafting densities and surface coverages, respectively, for the PMMA brushes with various pattern resolutions. In the mushroom-like regime, the distance between lines of PMMA brushes was smaller than that of the lines patterned lithographically on the wafer; in the brush-like regime, this distance was approximately the same. This new strategy allows polymer brushes to be prepared through graft polymerization and then have their patterns varied through solvent immersion. (C) 2009 Elsevier Inc. All rights reserved.
Using Solvent Immersion to Fabricate Variably Patterned Poly(methyl methacrylate) Brushes on Silicon Surfaces
(2008-11-25)
Chen, Jem-Kun
;
Hsieh, Chih-Yi
;
Huang, Chih-Feng
;
Li, P. -M.
;
Kuo, Shiao-Wei
In this paper we describe a graft polymerization/solvent immersion method for generating various patterns of polymer brushes. We used a very-large-scale integration (VLSI) process to generate well-defined patterns of polymerized methyl methacrylate (MMA) on patterned Si(100) surfaces. A monolayer of Si(CH3)(3) groups was first generated to form an inert surface by reacting a hydroxylated Si surface with hexamethyldisilazane in a thermal evaporator. Oxygen plasma was the used to reactivate the patterned surface under a duty ratio of 1: 1 using electron beam lithography. The surface-generated oxygen species, such as Si-O and Si-O-O, reacted with the initiator for atom transfer radical polymerization (ATRP) on the patterned hydroxylated surface. The ATRP initiator on the patterned surface was then used for the graft polymerization of MMA to prepare the PMMA brushes. After immersion of wafers presenting lines and dots of these PMMA brushes in water and tetrahydrofuran, we observed mushroom- and brush-like regimes, respectively, for the PMMA brushes with various pattern resolutions.