  We investigate the temperature dependent phase behaviour of mixtures of
poly(Nisopropylacrylamide) (pNIPAM) microgel colloids and a triblock copolymer
(PEO-PPO-PEO) surfactant, which undergoes micellisation. Gelation in these
systems results from an increase in temperature. Here we alter the heating rate
and observe that the mechanism for aggregation changes from one of depletion of
the microgels by the micelles at low temperatures to association of the two
species at high temperatures. We use this to access multiple structures at one
microgel concentration. Samples with a micelle concentration above 7 wt% were
found to demix into phases rich and poor in microgel particles at temperatures
below 33 degrees, under conditions where the microgels particles are partially
swollen. Under rapid heating full demixing is bypassed and gel networks are
formed instead. The temperature history of the sample therefore allows for
kinetic selection between different final structures, which may be metastable.
