Dynamic microprobing of viscoelastic polymer properties

✍ Scribed by Tsukruk, Vladimir V; Gorbunov, Valery V; Huang, Zheng; Chizhik, Sergey A

• Publisher: John Wiley and Sons
• Year: 2000
• Tongue: English
• Weight: 144 KB
• Volume: 49
• Category: Article
• ISSN: 0959-8103
• DOI: 10.1002/(sici)1097-0126(200005)49:5<441::aid-pi240>3.0.co;2-u

✦ Synopsis

Scanning force microscopy (SFM) was used to probe the micromechanical properties of polyisoprene rubbers, polyurethanes, polystyrene and polyvinylchloride. Applicability of the SFM cantilevers for microprobing is presented as a convenient method for materials selection. The Hertzian model of elastic contacts was used to obtain Young's modulus at contact frequencies range 0.05±367 Hz. The absolute values of the elastic modulus were correlated with the known properties of bulk materials, with no frequency dependence detected for glassy polyvinylchloride and polystyrene in air. The time dependence of the Young's modulus of rubber and polyurethanes followed the Williams±Landel±Ferry relationship, with parameters known for bulk materials. For PVC in water, a signi®cant reduction of the elastic modulus and strong time-dependency were recorded. This behaviour can be related to the lower local glass transition temperature because of a plasti®cation effect of solvent molecules on the uppermost polymer layer.