Simulation Study On The Loading And Releasing Hydrocarbon Molecules Of The PH-response Copolymer:PAE-PEG

Hydrophobic poly(?-amino ester)(PAE)and hydrophilic methyl ether-capped poly(ethylene glycol)(PEG)is a double block copolymer with pH response characteristics,it is self-assembled in neutral solution to form nano-multilayer structure loading micelles and produces a stimulus response in an acidic solution,releasing the loaded material rapidly,thus achieving controlled release of the loaded material.As a result,it is widely used as an intelligent delivery system,which is formed by self-assembly.In this paper,a single/mixed component hydrocarbon molecule(alkane/olefin/aromatics)loaded/released by PAE-PEG is studied.Microcosmic/mesoscopic process,structure and properties of copolymer loading/releasing are explored by dissipative particle dynamics simulation method.It provides some theoretical guidance for the application of copolymer emulsion demulsifier to oilfield chemistry.The main research contents of the thesis are as follows:The results of copolymer loading/releasing a single component hydrocarbon molecule show that the copolymer and hydrocarbon molecules gather together to form spherical micelles,the PAE groups form hydrophobic cores,the PEG groups form hydrophilic layers,the hydrocarbon molecules enter the micelles,the repulsive force parameters are smaller,and the hydrocarbon molecules are distributed in the outer layers of the micelles in the neutral aqueous solution,the more stable the dynamic properties of the micelles,the higher the loading efficiency of the micelle;the copolymer is completely proton to become hydrophilic,most of the diffusion enters the water phase,and a few links to the "oil droplet" surface formed by the hydrocarbon molecules themselves to reach a completely released state in acidic aqueous solution,the greater the hydrophile-lipophile balance energy of copolymer molecule,the more unstable the dynamic property,the faster the release and the higher releasing efficiency.The final results show that the molecular capacity of micelle loading and releasing hydrocarbon is alkane > olefin > aromatics.The results of copolymer loading/releasing a mixed component hydrocarbon molecule show that the micelle formation process is the same as that of a single component system,wherein the distribution structure of a hydrocarbon molecule in the micelles is the same as that of a single component system,the dynamic property of the whole micelle is more stable and the loading efficiency of the micelle is higher in the neutral aqueous solution;the copolymer is completely proton to become hydrophilic,the hydrophile-lipophile balance energy of copolymer in the mixed system is larger than that of copolymer in the single system,the copolymer molecule is released from the surface of "oil droplet" and enters into the water phase to complete releasing state.The final results show that the molecular capacity of micellar loading/releasing mixed component hydrocarbon molecule is alkane/aromatics > alkane/olefin > olefin/aromatics > alkane/olefin/aromatic,loading/releasing of two-component hydrocarbon molecular capacity is greater than loading/releasing three-component hydrocarbon molecule capacity,loading/releasing three-component hydrocarbon molecular capacity is greater than loading/releasing single-component hydrocarbon molecule capacity.