We intend to study the phase behaviour of 2 cationic polythiophenes, P3MAHT and P3ImiHT, inthe presence of the perfluorinated surfactant (C8 chain) PFOS and its hydrogenated analogue SOS in D2O. Our main objective for this experiment is to determine the solution structure of both polymers as a function of surfactant mole fraction using SANS, and to determine the corresponding phase diagrams. Additionally, we intend to study the effect of temperature (20-80 C) on the size and organisation of the complexes formed in the related P3MAHT-SDSx system (SDS = C12) Changes in the organisation of the polymer-surfactant complexes should yield a dramatic influence on the photophysical properties, which will also be investigated using optical spectroscopy.