Poly(N-isopropyl acrylamide) brush topography: Dependence on grafting conditions and temperature

B. C. Choi, S. Choi, Deborah E Leckband

Research output: Contribution to journalArticle

Abstract

The topography of poly (N-isopropyl acrylamide) brushes end-grafted from initiator-terminated monolayers was imaged by atomic force microscopy, as a function of the area per chain and of solvent quality. Measurements were done in air and in water, below and above the lower critical solution temperature. At low grafting densities and molecular weights, area-averaged ellipsometry measurements did not detect changes in the volume of water-swollen, end-grafted polymer films above the lower critical solution temperature. However, atomic force microscopy images revealed surface features that suggest the formation of lateral aggregates or "octopus micelles". At high grafting densities and molecular weights, the films collapsed uniformly, as detected by both AFM imaging and ellipsometry. These findings reconcile in part prior results suggesting that some poly(N-isopropyl acrylamide) chains do not collapse in poor solvent, and they also reveal more complex collapse behavior above the lower critical solution temperature than is commonly assumed. This behavior would influence the ability to tune the functional properties of poly(N-isopropyl acrylamide) coatings.

Original languageEnglish (US)
Pages (from-to)5841-5850
Number of pages10
JournalLangmuir
Volume29
Issue number19
DOIs
StatePublished - May 14 2013

Fingerprint

brushes
Brushes
Topography
topography
Ellipsometry
atomic force microscopy
ellipsometry
molecular weight
Atomic force microscopy
octopuses
Molecular weight
Water
Micelles
initiators
Polymer films
Temperature
water
temperature
Monolayers
micelles

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Spectroscopy
  • Electrochemistry

Cite this

Poly(N-isopropyl acrylamide) brush topography : Dependence on grafting conditions and temperature. / Choi, B. C.; Choi, S.; Leckband, Deborah E.

In: Langmuir, Vol. 29, No. 19, 14.05.2013, p. 5841-5850.

Research output: Contribution to journalArticle

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