English Abstract

Novel Viscoelasticity Measurement Method Based on AFM Force Mapping and JKR Analysis

Toshio NISHI
WPI Advanced Institute for Materials Research, Tohoku University,Aoba-ku Sendai, 980-8577, Japan
Nippon Gomu Kyokaishi,(2011),84(6),171-175 Original Paper in Japanese

The Johnson-Kendall-Roberts (JKR) elastic contact model has been mostly applied for the analyses of force-distance curve measurements. We employed an AFM force mapping measurement on natural rubber (NR)/butyl rubber (IIR) vulcanized blend. The force-distance curve fitted well to the JKR model on elastic NR and rigid zinc oxide region but did not on viscoelastic IIR region. We calculated the deviated areas surrounded by a JKR curve and a experimental plot and mapped them to two-dimensional image. The derived image emerged viscoelastic IIR region from other rigid or rubbery region. This deviation will be due to viscoelastic properties of the materials; the glass transition temperature of IIR is close to the measurement condition. While whole energy dissipation of a cycle of each force-distance curve is strongly affected by adhesive hysteresis, the method we proposed here is free from adhesion because it calculates a difference from the JKR theory, in which adhesion is taken into consideration.

Keywords: Atomic Force Microscopy, Force-distance Curve, Force Mapping, Force Volume, Nanomechanical Properties, Viscoelasticity, JKR Analysis