In this work, the poly(methyl methacrylate-co-pentafluorophenyl acrylate) [P(MMA-co-PnFPA)] copolymer by dispersion polymerization in supercritical carbon dioxide was prepared. The physicochemical properties for the P(MMA-co-PnFPA) were investigated with varied mole ratios of MMA vs PnFPA (20:1, 25:1 and 30:1), and 1.0 wt%, 2.0 wt% and 4.0 wt% AIBN amounts. Experimental cloud-point data up to 453 K and 220 MPa are measured for binary and ternary mixtures of P(MMA-co-PnFPA) in supercritical CH2F2, CHF3 and CHCIF2. Phase behavior of binary systems for the P(MMA-co-PnFPA) [mole ratio = 25:1, AIBN: 1.0 wt% (M-w = 173,000), 2.0 wt% (M-w =93,600), and 4.0 wt% (M-w = 74,600)] + CH2F2 (or CHF3 and CHClF2) mixtures at temperature range from 333K to 434K and pressure up to 153 MPa are measured the upper critical solution temperature (UCST) type behavior with negative slope for the P(MMA-co-PnFPA)+ CH2F2, and lower critical solution temperature (LCST) type curve with positive slope for the P(MMA-co-PnFPA)+ CHF3 and P(MMA-co-PnFPA)+ CHCIF2 mixtures. Cloud-point curves for the P(MMA-co-PnFPA) [mole ratio= 20:1 (M-w =170,000), 25:1 (M-w =173,000), and 30:1 (M-w =228,000); 1.0 wt% AIBN] + supercritical (CH2F2, CHF3 and CHCIF2) mixtures show a negative slope for the P(MMA-co-PnFPA)+ CH2F2, and a positive slope for the P(MMA-co-PnFPA)+ CHF3 and P(MMA-co-PnFPA)+ CHCIF2 mixtures at temperature to 453 K and pressure up to 160 MPa. Also, the impact of MMA (or CHCIF2) on phase behavior for the P(MMA-co-PnFPA) (25:1; 1.0 wt% AIBN) + CH2F2 mixtures are measured in changes of the pressure-temperature (p, T) slope from UCST behavior to LCST behavior, and with MMA (or CHCIF2) cosolvent concentrations of (0.0-28.9) wt% (or CHCIF2: 0.0-97.2 wt%). (C) 2016 Elsevier B.V. All rights reserved.