Monolayer Formation of PBLG-PEO Block Copolymers at the Air-Water Interface

Published

November 11, 2004

Author(s)

Y Park, Y W. Choi, SK Park, C S. Cho, Michael J. Fasolka, Daeson Sohn

Abstract

Physicochemical properties of PBLG (poly(gamma-benzyl-L-glutamate))-PEO (poly(ethylene oxide)) diblock copolymers composed of PBLG as the hydrophobic rod component and PEO as the hydrophilic component were investigated at the air-water interface. Surface pressure-area isotherms obtained by the Wilhelmy plate method provide several variables such as molecular size, compressibility of PEO, and the free energy change of the PBLG-PEO block copolymer. GE-1 (M-w of PBLG:PEO = 103,700:12,000), with a relatively longer rod, has negative temperature effects and GE-3 (M-w of PBLG:PEO = 8400:12,000), with a relatively shorter rod, shows a positive temperature effect because of the large entropy loss.These competitions were based on the block size of PBLG and PEO and were affected by various microstructures of the PBLG-PEO diblock copolymer. Monolayer aggregations transferred onto mica from the air-water interface were analyzed with AFM. AFM images of GE-1 monolayers show cylindrical micelles, but the self-assembled structure has many large domains. The monolayer of GE-2 (M-w of PBLG:PEO = 39,800:12,000), which has a medium size rod, forms a spherical structure at the air-water interface. Monolayers of GE-3, with a short rod length, form bilayer structures. These results demonstrate that the microstructures of PBLG-PEO diblock copolymers are related to free energy changes between rod and coil blocks.

Proceedings Title

283 (2)

Conference Dates

March 15-16, 2005

Conference Location

Undefined

Conference Title

Journal of Colloid and Interface Science

Pub Type

Conferences

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Keywords

block copolymer, compressibility, Langmuir-Blodgett, PBLG-PEO, surface pressure

Citation

Park, Y. , Choi, Y. , Park, S. , Cho, C. , Fasolka, M. and Sohn, D. (2004), Monolayer Formation of PBLG-PEO Block Copolymers at the Air-Water Interface, 283 (2), Undefined, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=852533 (Accessed April 19, 2024)