2018 Henk Lekkerkerker

Henk Lekkerkerker (Utrecht) right with Piotr Warszynsk

Henk Lekkerkerker worked in colloids and interfaces in his entire carrier, first in Brussels and then as van’t Hoff professor in Utrecht, emeritus now. He was Elected president of the ECIS society in 1996, always working in the ECIS-ECIC fusion of memberships and meetings that was achieved by Helmuth Möhwald and Hans Lyklema. He won the Rhodia prize 2003 in Firenze for the effect of anisometry of colloids in smectic-nelatic-columnar phases of colloids 
    In the 70s, initially Henk was performing light scattering, turbidity, osmotic compressibility UC: redoing Jean Perrin experiment in another form to check Einstein diffusion-sedimentation. One of most general results acquired when ECIS started in the late 80s, was the thermodynamic stability of nematic phases, a direct proof of Onsager and Frenkel assumptions, are still now a major result that with remain in the core of colloid text-books. 
    Henk’s five major results, now part of common knowledge in the field of colloids and described in all textbooks I know, are:nematic and smectic phase diagrams of rod-like and plate-like hard and charged colloids (early eighties, results presented as contributing oral in several ECIS meetingsbidispersity can translate in coexisting liquid crystalline phasesphase diagrams induced by depletion forces , colloids with adsorbing and non-adsorbing polymersphase behaviour of colloids of mixed shapes, including quantitative effect of depletion in terms of entropysedimentation and off-equilibrium liquid crystals of colloids. 
    Beyond fundamental interest, no formulation of systems containing alumina-based prism shaped colloids, for instance in car “metallic” paints, are envisaged without using the fundamental relation Henk Lekkerkerker established. 
    Even some “minor” results, such as the effect of charges on bending free energy of thin films, are still of major importance (early 90s). 
    Doing this, he is part of the leading scientists maintaining the Dutch school, not large in numbers, but still at cutting edge of Colloid science. This started with Overbeek; then Vrij (stability of polydisperse colloids); then Lyklema ( electrokinetic effects bridging colloids and electrochemistry) and then Lekkerkeker (the behaviour of anisometric colloids, with Philipse in the future. 
    Vrij and Lyklema are not in the list of Overbeek medalists, so it seems to me important that Henk, former President and scientist active in ECIS having delivered major results in ECIS meetings, at the root of depletion and anismetry in colloids phase diagram and sedimentation a core knowledge of nanoscience beyond electronics