Soft matter is a subfield of
condensed matter comprising a variety of physical systems that are deformed or structurally altered by thermal or mechanical stress of the magnitude of thermal fluctuations. They include
liquids,
colloids,
polymers,
foams,
gels,
granular materials,
liquid crystals, and a number of
biological materials. These materials share an important common feature in that predominant physical behaviors occur at an
energy scale comparable with
room temperature thermal energy. At these temperatures,
quantum aspects are generally unimportant.
Pierre-Gilles de Gennes, who has been called the "founding father of soft matter," received the
Nobel Prize in physics in 1991 for discovering that methods developed for studying
order phenomena in simple systems can be generalized to the more complex cases found in soft matter, in particular, to the behaviors of
liquid crystals and
polymers. He is especially noted for inventing the concept of
reptation.