IMPORTANCE OF CONTROLLING INTERPARTICLE GAPS FOR NOVEL MATERIAL PROPERTIES

Measurement of average interparticle gap in chains of colloidal particles is realized by means of light scattering in silica suspensions or dynamic mechanical analysis in MR elastomers. For a silica volume fraction of 10% we find that the mean distance between particles inside chains drop off sharply with the increase of field; this behavior is attributed to the presence of a long range ionic repulsive force. We show that this experiment allows to obtain information about interparticle forces between colloidal particles. On the other hand the transmitted light is very sensitive to the size of the particles in the chain and to the gap between particles. In an other domain, namely elastomers containing chains of magnetic particles, the magnetostriction is also found to be determined by the interparticle gap.