Effect of Grafting Density of Random Copolymer Brushes on Perpendicular Alignment in PS-b-PMMA Thin Films
Type
ArticleAuthors
Lee, WooseopPark, Sungmin
Kim, Yeongsik
Sethuraman, Vaidyanathan
Rebello, Nathan
Ganesan, Venkat

Ryu, Du Yeol

Date
2017-07-18Online Publication Date
2017-07-18Print Publication Date
2017-08-08Permanent link to this record
http://hdl.handle.net/10754/625791
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Show full item recordAbstract
We modulated the grafting density (σ) of a random copolymer brush of poly(styrene-r-methyl methacrylate) on substrates to probe its effect on the formation of perpendicularly aligned lamellae of polystyrene-b-poly(methyl methacrylate) (PS-b-PMMA). Supported by coarse-grained simulation results, we hypothesized that an increase in σ will allow us to systematically tune the block copolymer interfacial interactions with the substrates from being preferential to one of the blocks to being neutral toward both blocks and will thereby facilitate enhanced regimes of perpendicularly aligned lamellae. We verified such a hypothesis by using a simple grafting-to approach to modify the substrates and characterized the thickness window for perpendicular lamellae as a function of brush thickness (or σ) on the grafted substrates using scanning force microscopy (SFM) images and grazing incidence small-angle X-ray scattering (GISAXS) measurements. The experimental results validated our hypothesis and suggested that the σ of random copolymer brushes can be used as an additional versatile parameter to modulate the interfacial interactions and the resulting alignment of block copolymer films.Citation
Lee W, Park S, Kim Y, Sethuraman V, Rebello N, et al. (2017) Effect of Grafting Density of Random Copolymer Brushes on Perpendicular Alignment in PS-b-PMMA Thin Films. Macromolecules 50: 5858–5866. Available: http://dx.doi.org/10.1021/acs.macromol.7b00133.Sponsors
V.G. acknowledges funding in part by grants from the Robert A. Welch Foundation (Grant F1599), the National Science Foundation (DMR-1306844), and King Abdullah University of Science and Technology (OSR-2016-CRG5-2993-1). Acknowledgment is also made to the Donors of the American Chemical Society Petroleum Research Fund for partial support of this research (56715-ND9). D.Y.R. acknowledges funding by the NRF grants (2017R1A2A2A05001048, 2017R1A4A1014569) and funding (20163030013960) from the Korea Institute of Energy Technology Evaluation and Planning (KETEP) and the Ministry of Trade, Industry & Energy (MOTIE), Korea.Publisher
American Chemical Society (ACS)Journal
Macromoleculesae974a485f413a2113503eed53cd6c53
10.1021/acs.macromol.7b00133