▁of ▁the ▁E cole ▁N ationale ▁des ▁Pont s ▁et ▁Ch auss és ▁( EN PC ) ▁in ▁ 2 0 1 5 . ▁ ▁Basic ▁sciences ▁and ▁industrial ▁innov ations ▁ ▁R oux ' s ▁career ▁is ▁based ▁above ▁all ▁on ▁the ▁work ▁of ▁a ▁fundamental ist ▁research er ▁who ▁has ▁long ▁been ▁cent red ▁around ▁the ▁phys ico - chem istry ▁of ▁cond ensed ▁matter . ▁His ▁most ▁significant ▁works ▁correspond ▁to ▁studies ▁at ▁equilibrium ▁and ▁out ▁of ▁equilibrium ▁of ▁the ▁behaviour ▁of ▁partially ▁organized ▁phases ▁( liqu id ▁cry st als , ▁col lo ids , ▁sur fact ants ▁in ▁solution ... ). ▁On ▁the ▁one ▁hand , ▁they ▁were ▁based ▁on ▁both ▁an ▁experimental ▁and ▁theoretical ▁mod elling ▁approach ▁to ▁describe ▁and ▁understand ▁the ▁behaviour ▁of ▁very ▁flexible ▁surfaces ▁subject ed ▁to ▁thermal ▁fl uct u ations ▁( fl uct u ating ▁surfaces ). ▁This ▁has ▁made ▁it ▁possible ▁to ▁obtain ▁a ▁universal ▁vision ▁of ▁the ▁behaviour ▁of ▁these ▁surfaces ▁by ▁highlight ing ▁in ▁particular ▁the ▁existence ▁of ▁und ulation ▁interactions ▁between ▁memb ran es ▁and ▁the ▁discovery ▁of ▁memb rane ▁phases ▁randomly ▁connected ▁in ▁space ▁( sp on ge ▁phase ).   ▁On ▁the ▁other ▁hand , ▁his ▁work ▁on ▁the ▁out - of - equ ilib rium ▁study ▁of ▁these ▁phases ▁has ▁allowed ▁us ▁to ▁discover ▁a ▁new ▁type ▁of ▁inst ability , ▁thus ▁dram atically ▁illustr ating ▁the ▁struct ural ▁change ▁of ▁the ▁frag ile ▁material ▁subject ed ▁to ▁a ▁flow ▁( transition ▁under ▁flow ▁from