The elastic modulus and work of adhesion of thin polystyrene (PS) films have been evaluated from nanoindentation load-displacement curves. The modulus was calculated using two methods: an unloading stiffness analysis and an elastoplastic unloading analysis. Results indicate that the latter analysis gives better modulus evaluation for the polymers. Two methods were also utilized in determining the work of adhesion, one using the pull-off forces and one using the displacement difference at zero force and pull-off force. The values given by the two methods are close. The effects of surface roughness and maximum load on the adhesion measurements are discussed. Different molecular weights were also chosen to compare the characteristics of the polymers during use under the same conditions. No significant difference in either modulus or adhesion energy was shown between the PSs of very low, moderate, and high molecular weights at room temperature.
|Original language||English (US)|
|Journal||Materials Research Society Symposium - Proceedings|
|State||Published - 2001|
|Event||Fundamentals of Nanoindentation and Nanotribology II - Boston, MA, United States|
Duration: Nov 28 2000 → Nov 30 2000
Bibliographical noteFunding Information:
The authors would like to thank Prof. Marc A. Hillmyer of the University of Minnesota for his comments and suggestions. We also thank Jason S. Ness for synthesizing the PSs. This research was initially supported by the Center for Interfacial Engineering which was an NSF ERC. The Hysitron TriboScopeTM and AFM are part of the Characterization Facility of the University of Minnesota.
Copyright 2004 Elsevier Science B.V., Amsterdam. All rights reserved.