The effect of cosolvents (ethanol

acetone

n-heptane) on the supercritical CO2 system were evaluated through the multi-scale molecular modeling and dissolution behavior measurement

which might improve the solvent-solvent and solvent-solute interactions and enhance the compatibility with polymer. The ab initio calculation showed that the interaction between ethanol and CO2 was the strongest one

followed by that of acetone and n-heptane. The molecular dynamics simulations indicated that ethanol significantly increased the solubility parameter of solvent

and the interaction of supercritical CO2-ethanol with PVAc chain was stronger than that of the other two at the same co-solvent content

which was helpful to improve the compatibility between PVAc and the solvent. The interaction between ethanol and CO2 was the strongest due to the bigger solubility parameter of ethanol and the obvious hydrogen bond between ethanol and CO2.The cloud point experiments confirmed that ethanol was the most effective to reduce the cloud point pressure of PVAc. The addition of cosolvent enhanced the compatibility of supercritical CO2 system with PVAc

and the solubility of PVAc in supercritical CO2-cosolvent increased with the mole fraction of cosolvent.