Visualization of strain distribution in rubber bulk during friction.

This study employed a digital image correlation method (DICM) to experimentally quantify horizontal strain distribution in silicone rubber bulk during horizontal displacement against a stainless-steel sphere with/without glycerol. The strain distribution at different depth levels was measured by capturing the position of white powders in transparent rubber bulk. The experimental results indicated that each point in the rubber bulk moved while describing a horizontal loop during horizontal displacement depending on the position and lubrication conditions. This caused changes in the horizontal strain during horizontal displacement. These results suggest that the hysteresis term could be caused by changes in the vertical and horizontal strains.

Induced smectic phases of stoichiometric liquid crystal mixtures.

We revealed the detailed structures of induced smectic liquid crystal (LC) phases composed of a binary mixture of charge-transfer (CT) LC substances. Although neither of the constituents had highly ordered smectic phases, the mixture exhibited smectic-E (SmE) or smectic-B (SmB) phases when mixed at ratios of 1 : 1 and 2 : 3, respectively. The results of polarized optical microscopy, differential scanning calorimetry, X-ray diffraction, and infrared spectroscopy indicated that the induced smectic phases were stabilized by an exquisite balance between the CT interactions, dipolar interactions, and excluded volume effects. We proposed a possible model for the molecular arrangements in the SmE and SmB phases, which consistently explained the experimental results including the stoichiometric ratios.