Kinetics of thermo-responsive diblock copolymer films consisting of two LCST-type blocks:In a set of recent experiments we have investigated the swelling and switching of thermo-responsive homopolymer and copolymer films, which exhibit a lower critical solution temperature (LCST) type phase transition from a swollen to a collapsed chain conformation. Such films are nano-scale sensors. The thermal response of these sensor films to e.g. a temperature change from below LCST to above LCST showed an unexpected behavior, which has been related to the chain collapse and water release, relaxation and reswelling. In the proposed experiment we want to expand this work to diblock copolymer films which consist of two thermo-responsive blocks with different LCST-type transition temperatures (TT1 and TT2). These films can be used for more complex sensor architectures. At the instrument D17 we are able to follow the kinetics of the transition from a swollen to a collapsed hydrogel film with neutron reflectivity with a time resolution better than 10 seconds! Deuterated water (D2O) is used to achieve a high contrast.