Atomic force microscopy measurements of adsorbed polyelectrolyte layers. 2. Effect of composition and substrate on structure, forces, and friction
2003 (English)In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 19, no 10, 4180-4187 p.Article in journal (Refereed) Published
An investigation on the effect of the conformation of preadsorbed polyelectrolyte layers of acrylamide-1% [3-(2-methylpropionamide)propyl]trimethylammonium chloride on the normal and lateral interactions between surfaces has been conducted. It was shown that when bridging mechanisms increased the adhesion, huge increases in the friction were also seen. When the polymer adsorbed in an extended layer, it resulted in a steric repulsion in the direction normal to the interface. However, the resulting friction measurements were shown to be far more complicated. For example, in cases where the integrity of the polymer layer was maintained under compression, the layer was able to act as a lubricant; however when the layer integrity was affected by the load and shear rate, then friction increased due to energy losses resulting, from disrupting the polymer conformation. The conformation was controlled by varying both the polymer charge density and the nature of the surface. The interaction between the polyelectrolyte and gold proved to be significantly stronger than that with silica, rendering the polymer layer more resistant to damage under shear and, consequently, a significantly different friction-load relationship. The dynamics of the interactions were also investigated and were highly dependent on the polyelectrolyte-surface interaction. As an aside, a novel observation of interference effects between cantilever and substrate is also made.
Place, publisher, year, edition, pages
2003. Vol. 19, no 10, 4180-4187 p.
torsional spring constant, cationic polyelectrolyte, surface forces, dodecyl-sulfate, good solvent, shear, adsorption, cellulose, tribology, liquid
IdentifiersURN: urn:nbn:se:kth:diva-22489DOI: 10.1021/la026571hISI: 000182781500018OAI: oai:DiVA.org:kth-22489DiVA: diva2:341187
QC 201005252010-08-102010-08-10Bibliographically approved