Effects of copolymer concentration and chain length on the pH-responsive behavior of diblock copolymer micellar films

Sakai, Kenichi, Smith, Emelyn G., Webber, Grant B., Wanless, Erica J., Butun, Vural, Armes, Steven P. and Biggs, Simon (2006) Effects of copolymer concentration and chain length on the pH-responsive behavior of diblock copolymer micellar films. Journal of Colloid and Interface Science, 303 2: 372-379. doi:10.1016/j.jcis.2006.07.077


Author Sakai, Kenichi
Smith, Emelyn G.
Webber, Grant B.
Wanless, Erica J.
Butun, Vural
Armes, Steven P.
Biggs, Simon
Title Effects of copolymer concentration and chain length on the pH-responsive behavior of diblock copolymer micellar films
Journal name Journal of Colloid and Interface Science   Check publisher's open access policy
ISSN 0021-9797
1095-7103
Publication date 2006-11-15
Sub-type Article (original research)
DOI 10.1016/j.jcis.2006.07.077
Open Access Status Not yet assessed
Volume 303
Issue 2
Start page 372
End page 379
Total pages 8
Place of publication Maryland Heights, MO, United States
Publisher Academic Press
Language eng
Formatted abstract
The pH-responsive behavior of adsorbed diblock copolymer films of PDMA-PDEA (poly(2-(dimethylamino)ethyl methacrylate)-block-poly(2-(diethylamino)ethyl methacrylate)) on silica has been characterized using a quartz crystal microbalance with dissipation monitoring (QCM-D), an optical reflectometer (OR) and an atomic force microscope (AFM). The copolymer was adsorbed at pH 9 from various copolymer concentrations; QCM-D measurements indicate that the level of desorption when rinsed at pH 9 depends on the initial copolymer concentration. The adsorbed films produced at pH 9 generally have low charge densities; adjusting the solution pH to 4 results in a significant protonation of the constituent copolymers and a related interfacial structural change for the copolymer film. OR studies show no significant change during pH cycling, while QCM-D measurements indicate that the adsorbed mass and dissipation alter dramatically in response to the solution pH. The difference between the QCM-D adsorbed masses and dissipation values at pH 4 and 9 were found to be dependent on the initial copolymer concentration. This is due to differences in the initial conformations within the adsorbed copolymer layers at pH 9. The effect of the PDMA chain length on the pH-responsive behavior has also been studied; both the QCM-D adsorbed mass and dissipation of PDMA54-PDEA24 (shorter PDMA block) at pH 4 and 9 were observed to be greater than those of PDMA9X-PDEA2Y (longer PDMA block). This suggests that the normal extension of the adsorbed PDMA54-PDEA24 copolymer films is more significant than that of the PDMA9X-PDEA2Y films on silica.
Keyword Adsorption
Desorption
Optical reflectometry
PH-Responsive diblock copolymer
QCM-D
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collection: Faculty of Engineering, Architecture and Information Technology Publications
 
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