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Please use this identifier to cite or link to this item: http://hdl.handle.net/1959.3/231565
- Conformation of adsorbed layers of polyNIPAM on silica in a binary solvent
- Notley, Shannon M.
- The conformation of poly(N-isopropylacrylamide) chains adsorbed at a silica interface was studied as a function of concentration in the methanol-water binary solvent mixture. Both water and methanol are good solvents for PNIPAM; however, in certain mixtures cononsolvency is induced by a lowering of the LCST. This led to a decrease in the extent of the PNIPAM layer away from the interface as measured using the colloidal probe technique in the poor solvent region. At low methanol concentrations but still in the good solvent region capillary bridging between the silica surfaces with adsorbed PNIPAM layers was observed due to the increased methanol concentration in this interfacial region over that of the bulk. Furthermore, adsorption measurements showed that PNIPAM adsorbed only weakly to the silica interface with a low surface excess on the order of 0.23 mg/m2, which allowed study of the behavior of the immobilized PNIPAM chains under highly dilute conditions using the quartz crystal microbalance. As the concentration of methanol increased toward the phase transition boundary, a slight contraction followed by an expansion of the PNIPAM was observed, which is in agreement with previous predictions from theory for polymers in solution.
- Publication type
- Journal article
- Journal of Physical Chemistry B, Vol. 112, no. 40 (Oct 2008), pp. 12650-12655
- Publication year
- FOR Code(s)
- 02 Physical Sciences; 03 Chemical Sciences; 09 Engineering
- ABS resins; Acrylic acid resin; Acrylic monomers; Adsorption measurements; Amides; Binary solvent mixtures; Colloidal probe techniques; Concentration process; Conformation; Cononsolvency; Interfacial regions; Isopropylacrylamide; Methanol concentrations; Molecular conformation; Organic solvents; Oxide minerals; Phase interfaces; Phase transitions; Poly-N-isopropylacrylamide; Poor solvents; Quartz crystal microbalances; Silica surfaces; Silicon dioxide; Solvents; Surface-active agents; Surfactant
- American Chemical Society
- Publisher URL
- Copyright © 2008 American Chemical Society.
- Additional information
- Supported by the Cooperative Research Centre for Functional Communication Surfaces (CRC SmartPrint).
- Peer reviewed