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Single-Molecule AFM Study of Polystyrene Grafted at Gold Surfaces.

Authors :
Al-Maawali, Sabah
Bemis, Jason E.
Akhremitchev, Boris B.
Haiying Liu
Walker, Gilbert C.
Source :
Journal of Adhesion. Oct2005, Vol. 81 Issue 10/11, p999-1016. 18p. 2 Diagrams, 3 Charts, 6 Graphs.
Publication Year :
2005

Abstract

Single-molecule studies under poor solvent conditions show that atomic force microscopy (AFM) measurements of contour lengths of polystyrene 12K and 17K relate well to gel permeation chromatography (GPC) data when grafting concentrations are low (not greater than 0.7 mM). Contact angles and ellipsometry have been used to characterize the surfaces and indicate low grafting densities at this grafting concentration. Persistence lengths ( p ) of different length polystyrene chains, when fitted to a WLC (worm-like chain) model, show values of p = 0.23 nm±0.10 nm and p = 0.25 nm±0.13 nm, for 12 K and 17 K polystyrene, respectively, when the persistence lengths are fitted to log-normal distributions. These values are close to the expected theoretical value of 0.23 nm and further confirm that mostly single molecules were studied on these polystyrene surfaces. Higher grafting concentrations (≥1 mM) resulted in pulling multiple molecules. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
00218464
Volume :
81
Issue :
10/11
Database :
Academic Search Index
Journal :
Journal of Adhesion
Publication Type :
Academic Journal
Accession number :
19019851
Full Text :
https://doi.org/10.1080/00218460500310416