The seven poly(methyl methacrylate-co-pentafluorophenyl methacrylate) [P(MMA-co-PnFPMA)] copolymers were prepared by dispersion polymerization under supercritical carbon dioxide. The physicochemical characterisation for the P(MMA-co-PnFPMA) was investigated with varied mole ratios of MMA vs PnFPMA (30:1, 25:1 and 20:1), AIBN amounts (1.0, 2.0 and 4.0 wt%) and the weight average molar mass (M-w). Experimental values at temperatures from (333 to 453) K and pressures up to 229 MPa are reported for binary and ternary mixtures of P(MMA-co-PnFPMA) in supercritical CO2, CH2F2, CHF3 and CHClF2. Phase behaviour of binary systems for the P(MMA-co-PnFPMA) (mole ratio = 25: 1, 1.0 wt%, 2.0 wt%, and 4 wt% AIBN) + supercritical fluoric solvents (CH2F2, CHF3 and CHClF2) mixtures at temperature range from (333 to 434) K and pressure up to 168 MPa are measured for the upper critical solution temperature (UCST) type behaviour with negative slope for the {P(MMA-co-PnFPMA) + CH2F2} as well as for the lower critical solution temperature (LCST) type curve with positive slope for the {P(MMA-co-PnFPMA) + CHF3} and {P(MMA-co-PnFPMA) + CHClF2} mixtures. Cloud-point curves for the {P(MMA-co-PnFPMA) [mole ratio = 30: 1 (M-w = 157,000), 25: 1 (M-w = 149,000), and 20: 1 (M-w = 142,000): 1.0 wt% AIBN; 30:1 (M-w = 109,000), 25: 1 (M-w = 94,000), and 20: 1 (M-w = 88,000): 2.0 wt% AIBN] + supercritical (CH2F2, CHF3 and CHClF2)} mixtures show a negative slope for the P(MMA-co-PnFPMA) + CH2F2, and a positive slope for the {P(MMA-co-PnFPMA) + CHF3} and {P(MMA-co-PnFPMA) + CHClF2} mixtures at temperatures to 435 K and pressures up to 150 MPa. Also, the impact of MMA on phase behaviour for the P(MMA-co-PnFPMA) (mole ratio = 25:1; AIBN: 1.0 wt% and 2.0 wt%) + CH2F2 mixtures are measured in changes of the (pressure + temperature) (p, T) slope from UCST behaviour to LCST behaviour, and with MMA co-solvent concentrations of (0.0 to 39.0) wt%. Phase behaviour for the {P(MMA-co-PnFPMA) + (14.7 to 96.4) wt% CHF3 [or (27.9 to 97.1) wt% CHClF2]} mixture in supercritical CO2 show favourably better (fluorocopolymer + solvents) interaction than (solvents + solvents) interaction, changing from a negative slope to a positive slope. (C) 2016 Elsevier Ltd. All rights reserved.