Soft matter

Soft matter comprises a variety of states that are perhaps best distinguished by being dominated by energies of order thermal energies at room temperature, more or less. At these temperatures quantum aspects are generally unimportant. Examples include polymers, liquid crystals, surfactants, foams, gels, membranes, biological matter of all sorts, granular media, etc. The realization that soft matter contains innumerable examples of symmetry breaking, generalized elasticity, and many fluctuating degrees of freedom has re-enervated classical fields of physics such as fluids (now generalized to non-Newtonian and structured media) and elasticity (membranes, filaments, and anisotropic networks are all important and common aspects).

Pierre-Gilles de Gennes received the Nobel Prize in physics in 1991 for his research about soft matter.