From Hidden Shear‐Elasticity to Opto‐ and Thermo‐Elastic Properties in Confined Polymer Melts and Viscous Liquids

The newly identified low frequency elasticity of mesoscopic liquids opens the route to identification novel dynamic liquid properties. Two experimental examples illustrating impact in optics and thermodynamics are presented. It is revealed that at scale, able convert mechanical energy optical thermal effects. fluids submitted a (∼Hz) shear strain (external stress), thus excluding coupling with molecular time scales. response probed using two situ methods accessing real isotropic phase crystals probing upon deformation. In both cases, identified: exhibits birefringence while ordinary exhibit cold hot waves synchronous excitation.