Sep, 2010
Effect of Grafting Density on Phase Transition Behavior for Poly(N-isopropylacryamide) Brushes in Aqueous Solutions Studied by AFM and QCM-D
MACROMOLECULES
- ,
- Volume
- 43
- Number
- 17
- First page
- 7269
- Last page
- 7276
- Language
- English
- Publishing type
- Research paper (scientific journal)
- DOI
- 10.1021/ma101113g
- Publisher
- AMER CHEMICAL SOC
The effect of grafting density on the phase transition behavior of poly(N-isopropylacrylamide) (PNIPAM) grafted onto a flat substrate was investigated using an atomic force microscope (AFM) and a quartz crystal microbalance (QCM-D). We prepared PNIPAM brush layers at three different grafting densities on silicon wafers using a "grafting from" atom transfer radical polymerization (ATRP) approach. AFM imaging in water at various temperatures showed that the transition behavior of the grafted PNIPAM chains from a brush-like to a mushroom-like morphology was dependent on the grafting density: the images change abruptly from essentially featureless to domain structures across the LCST for the low-density surface, whereas the change in the images becomes less abrupt with increasing polymer graft density. The QCM-D data also indicated a significant dependence of the layer properties on the grafting density, confirming the behavior differences suggested by the A FM images. In particular, the dissipation data strongly suggest that the magnitude of lateral aggregation for the PNIPAM chains depends on the grafting density. A similar effect of grafting density was also observed for the phase transition as a function of salt concentration in sodium sulfate solutions.
- Link information
-
- DOI
- https://doi.org/10.1021/ma101113g
- Web of Science
- https://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=JSTA_CEL&SrcApp=J_Gate_JST&DestLinkType=FullRecord&KeyUT=WOS:000281474500046&DestApp=WOS_CPL
- URL
- http://www.scopus.com/inward/record.url?eid=2-s2.0-77956395739&partnerID=MN8TOARS
- URL
- http://orcid.org/0000-0001-7603-1151
- ID information
-
- DOI : 10.1021/ma101113g
- ISSN : 0024-9297
- ORCID - Put Code : 42075280
- SCOPUS ID : 77956395739
- Web of Science ID : WOS:000281474500046