TY - JOUR A1 - Munz, Martin A1 - Sturm, Heinz A1 - Schulz, Eckhard T1 - Interphase Characterization via the Stiffness Contrast of a Scanning Force Microscope in Displacement Modulation Mode JF - Surface and interface analysis N2 - The physical properties as well as the thickness of the interphase between polymer and reinforcing phase are generally expected to show a strong influence on the macroscopic mechanical properties of composite materials. In this study the scanning force microscope (SFM) has been applied for detecting stiffness gradients near the interface between copper and epoxide. In displacement modulation mode the load exerted by the tip is modulated sinusoidally by vibrating the normal position of the cantilever or the sample. The corresponding amplitude of dynamic cantilever bending is related to local surface stiffness. Thus, using the SFM, the local mechanical properties of the surface under investigation can be probed. When scanning the tip across the reinforcement/polymer interface, the polymeric interphasial zone can be identified with the observed stiffness gradient. For a commercial epoxide based on diglycidyl ether of bisphenol A (DGEBA) cured with an amine-containing hardener, a stiffness gradient was detected that could be fitted by a Gaussian profile typical for diffusional processes. The width of the stiffness gradient was 280 nm. The observation is discussed in terms of interface-induced segregation processes between resin and hardener, as well as heat conduction mechanisms that can occur during the exothermic curing reaction. Both mechanisms are diffusional in nature and, via the local network structure, are expected to show some influence on the local stiffness of the cured epoxy. Copyright © 2000 John Wiley & Sons, Ltd. T2 - ECASIA 99 CY - Sevilla, Spain DA - 1999-10-04 KW - Scanning Force Microscopy KW - Surface properties KW - Nanomechanics KW - Interface/Interphase KW - Polymer-matrix composites (PMCs) KW - Adherends PY - 2000 DO - https://doi.org/10.1002/1096-9918(200008)30:1<410::AID-SIA846>3.0.CO;2-G SN - 0142-2421 SN - 1096-9918 VL - 30 IS - 1 SP - 410 EP - 414 PB - Wiley CY - Chichester AN - OPUS4-873 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -