In recent years ‘smart’ materials, such as NIPAM (N-isopropylacrylamide) based microgels, have undergone intensive research concerning their response to external stimuli such as temperature, solvent composition, ionic strength and pH.In this work we focus on the thermoresponsive behaviour of microgels, which are candidates for drug delivery systems with a temperature controlled drug release. For this systems different particle architectures are possible. Besides the usualmicrogel particles, core-shell systems or interpenetrating networks can be obtained by a two-step synthesis. A potential application for these systems are nano-actuators due to a very controllable swelling behaviour or micro reactors for catalysis with a tuneable access to catalytic particles inside the microgels. The internal structure of these systems is still under debate. But to tune the characteristics of the microgel particles concerning the above mentioned applications a detailed understanding of the dependency of both the overall shape and the internal structure of this specific particle architecture on the temperature is necessary.