고분자 복합 유체 내 소수성 회합 능력과 쌍성 이온을 가진 독창적 회합 나노 입자에 대한 유변학 연구

Abstract

This study reports a robust and straightforward approach to synthesize associative nanoparticles (ANPs) that can modify the rheological properties of aqueous polymer gel fluids. The ANPs were synthesized by grafting hydrophobically modified hygroscopic zwitterionic poly(2-methacryloyloxyethyl phosphorylcholine (MPC)-co-stearyl methacrylate (SMA)) brushes onto 20 nm sized silica NPs via surface-mediated living radical polymerization. SMA having an alkyl chain (C18) was copolymerized with MPC to induce hydrophobic interaction with the corresponding alkyl chain of associative polymers that were freely dissolved in the aqueous phase. The incorporation of the ANPs into the associative polymer solution significantly enhanced the viscosity of the solution by a factor of five. This observation indicates that the ANPs act as nanoscale particulate crosslinkers due to their effective association with the polymers in the solution, leading to the formation of an ANP-mediated polymer gel structure. The ANP-reinforced polymer gel system prepared herein exhibited improved tolerance to pH and salinity, which is attributed to the retarded polymer chain relaxation from the particulate crosslink junction point.|We introduce a flexible approach for synthesis of associative nanoparticles (ANPs), providing controlled attraction with associative polymer rheology modifier (APRM), while displaying ability to produce highly stable Pickering emulsions. The ANPs were synthesized by grafting hydrophobically modified hygroscopic zwitterionic poly (2-methacryloyloxyethyl phosphorylcholine (MPC)-co-stearyl methacrylate (SMA)) brushes onto 20 nm sized silica NPs via surface-mediated living radical polymerization. The ANPs-stabilized Pickering emulsion significantly enhanced their viscosity in the presence of the APRM. This observation indicates that the ANPs act as particulate coacervation agents at the interface due to their effective hydrophobic association with the APRM dissolved in the aqueous phase, which leads to generation of an ANP-mediated complex colloidal film. For this reason, the ANP-reinforced Pickering emulsion system produced herein exhibited improved tolerance to pH and salinity. The approach proposed in this study is indeed advantageous in that the formation of complex colloidal layer at the interface can provide the emulsion drops with a mechanically robust barrier, which guarantees the improved Pickering emulsion stability against harsh environmental factors.; We introduce a flexible approach for synthesis of associative nanoparticles (ANPs), providing controlled attraction with associative polymer rheology modifier (APRM), while displaying ability to produce highly stable Pickering emulsions. The ANPs were synthesized by grafting hydrophobically modified hygroscopic zwitterionic poly (2-methacryloyloxyethyl phosphorylcholine (MPC)-co-stearyl methacrylate (SMA)) brushes onto 20 nm sized silica NPs via surface-mediated living radical polymerization. The ANPs-stabilized Pickering emulsion significantly enhanced their viscosity in the presence of the APRM. This observation indicates that the ANPs act as particulate coacervation agents at the interface due to their effective hydrophobic association with the APRM dissolved in the aqueous phase, which leads to generation of an ANP-mediated complex colloidal film. For this reason, the ANP-reinforced Pickering emulsion system produced herein exhibited improved tolerance to pH and salinity. The approach proposed in this study is indeed advantageous in that the formation of complex colloidal layer at the interface can provide the emulsion drops with a mechanically robust barrier, which guarantees the improved Pickering emulsion stability against harsh environmental factors.