Specific comblike gradient copolymers made of metal-complexing CO2-phobic units and fluorinated CO2-philic units were designed to study their auto-association when solubilised in supercritical CO2 (scCO(2)). This paper shows that in-house SAXS measurements on scCO(2) systems are now possible thanks to both high-energy X-rays and specific high-pressure cell designed with beryllium windows. The copolymer system poly(1,1,2,2-tetrahydroperfluorodecylacrylate-co-4-(diphenylphosphino)styrene), poly(FDA-co-DPPS) was compared to homopolymer poly(FDA)-SH and more classical molecule, C8F17C2H4-SH (RfSH). The results show that the presence of the CO2-phobic part of the copolymer does not necessarily tend to favour auto-association due to the comblike gradient design. However, this CO2-phobicity favours inter-object correlation leading to aggregation. (C) 2016 Elsevier B.V. All rights reserved.