Local Multiphysics Studies of Epoxy Nanocomposites For Electronics Packaging
Abstract
In the no-cost extension period of this project, we investigated the local micro- and nanoscale electrical properties of polydimethylsiloxane (PDMS) matrix composites with 12 wt percent (below the electrical percolation threshold) and 20 wt percent (above the electrical percolation threshold) carbon black (CB) nanoparticles in the range of 0-60 percent tensile strain with the aid of an Atomic Force Microscope (AFM) and a microtensile apparatus we developed in the previous reporting periods. A comparison of macroscale 2D finite strain fields with microscale strain fields, obtained from AFM images and digital image correlation, showed that 50x25 micrometer2 specimen domains were a representative element describing the effective mechanical response of the PDMS-CB nanocomposites. Similarly, 25x12 m2 specimen domains provided consistent total current measurements as larger surface areas, thus serving as a representative element for the effective surface electrical response of PDMS-CB nanocomposites subjected to abroad range of strains. It was further shown that the transverse specimen contraction due to the Poisson's effect increased the initially low through-thickness electrical conductivity of PDMS with 12 wt percent CB (below the electrical percolation threshold), with a rapid increase in the local electric current taking place above 30 percent applied strain, also resulting in a transition of the local surface conductivity from tunneling to a combination of Ohmic (linear I-V characteristic) and tunneling (non-linear I-V characteristic and lower electric current).
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 13, 2014
- Accession Number
- AD1230352
Entities
People
- Ioannis Chasiotis
Organizations
- University of Illinois Urbana–Champaign