Journal
JOURNAL OF COLLOID AND INTERFACE SCIENCE
Volume 314, Issue 1, Pages 52-62Publisher
ACADEMIC PRESS INC ELSEVIER SCIENCE
DOI: 10.1016/j.jcis.2007.05.029
Keywords
adhesion; AFM; polyamide; nylon; Van der Waals; intermolecular force
Categories
Ask authors/readers for more resources
This work presents atomic force microscopy (AFM) measurements of adhesion forces between polyamides, polystyrene and AFM tips coated with the same materials. The polymers employed were polyamide 6 (PA6), PA66, PA12 and polystyrene (PS). All adhesion forces between the various unmodified or modified AFM tips and the polymer surfaces were in the range - 1.5 to -8 nN. The weakest force was observed for an unmodified AFM tip with a PS surface and the strongest was between a PS-coated tip and PS surface. The results point to both the benefits and drawbacks of coated-tip AFM force-distance measurements. Adhesion forces between the two most dissimilar (PA6-PS and PA66-PS) materials were significantly asymmetric, e.g., the forces were different depending on the relative placement of each polymer on the AFM tip or substrate. Materials with similar chemistry and intermolecular interactions yielded forces in close agreement regardless of placement on tip or substrate. Using experimental forces, we calculated the contact radii via four models: Derjaguin, Muller, and Toporov; Johnson, Kendall, and Roberts; parametric tip-force-distance relation; and a square pyramid-flat surface (SPFS) model developed herein. The SPFS model gave the most reasonable contact tip radius estimate. Harnaker constants calculated from the SPFS model using this radius agreed in both magnitude and trends with experiment and Lifshitz theory. (c) 2007 Elsevier Inc. All rights reserved.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available