- Title
- pH-responsive behavior of selectively quaternized diblock copolymers adsorbed at the silica/aqueous solution interface
- Creator
- Sakai, Kenichi; Smith, Emelyn G.; Webber, Grant B.; Baker, Murray; Wanless, Erica J.; Butun, Vural; Armes, Steven P.; Biggs, Simon
- Relation
- Journal of Colloid and Interface Science Vol. 314, Issue 2, p. 381-388
- Publisher Link
- http://dx.doi.org/10.1016/j.jcis.2007.06.018
- Publisher
- Academic Press
- Resource Type
- journal article
- Date
- 2007
- Description
- The desorption and subsequent pH-responsive behavior of selectively quaternized poly(2-(dimethylamino)ethyl methacrylate)-block-poly(2-(diethylamino)ethyl methacrylate) (PDMA–PDEA) films at the silica/aqueous solution interface has been characterized. The copolymer films were prepared at pH 9, where micelle-like surface aggregates are spontaneously formed on silica. The subsequent rinse with a copolymer-free electrolyte solution adjusted to pH 9 causes partial desorption of the weakly or non-quaternized copolymers, but negligible desorption for the highly quaternized copolymers. Further rinsing with a pH 4 electrolyte solution results in additional desorption and extension (swelling) of the remaining adsorbed copolymer film normal to the interface. This pH-responsive behavior is reversible for two pH cycles (9–4–9–4) as monitored by both quartz crystal microbalance with dissipation monitoring (QCM-D) and also ζ potential measurements. The magnitude of the pH-responsive behavior depends on the mean degree of quaternization of the PDMA block. Moreover, a combination of contact angle data, ζ potential measurements and in situ atomic force microscopy (AFM) studies indicates that the pH-responsive behavior is influenced not only by the number of cationic binding sites on the adsorbed copolymer chains but also by the adsorbed layer structure.
- Subject
- pH-responsive diblock copolymer; adsorption; desorption; quaternization
- Identifier
- http://hdl.handle.net/1959.13/33269
- Identifier
- uon:3142
- Identifier
- ISSN:0021-9797
- Language
- eng
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