Study On The Thermodynamics Of The Correlative System Of Saponin Aqueous Solution And Several Polymers

In recent years,the study of the interaction between polymers and surfactants has played an important role in the broad application and basic research of biomedicine.Moreover,the compound system of surfactants has better application performance than a single surfactant.Saponin is a complex glycoside compound,which is widely found in plants and has good water solubility.Most saponins can reduce the surface tension of the solution and have foaming properties and emulsifier effects.Because of the interfacial activity and unique behavior of saponins in the dispersion system,saponins are of great interest to researchers.In this paper,the thermodynamics of saponin aqueous solution and several high polymer related systems have been carried out using surface tension,conductivity and isothermal titration microcalorimetry.It not only enriches the research of polymer-containing systems,but also provides a theoretical basis for the research of saponins.This project was supported by the National Natural Science Foundation of China（No.21473085）to carry out the following work:Firstly,the interaction system of saponin and polyethylene glycol（PEG）of different molecular weight is determined.Using the methods of surface tension（ST）,isothermal titration microcalorimetry（ITC）and spectrophotometer,The influence of different PEG molecular weights on the surface tension and critical micelle concentration（CMC）of saponins in aqueous solution was determined,and it was found that the overall surface tension of saponin in the PEG solution decreased obviously,and different molecular weight of PEG solution can have a corresponding effect on the micellar aggregation degree of saponin,the molecular force from electrostatic effect to hydrophobic effect.Secondly,the experiment selects saponins and（1-Dodecyl）trimethylammonium bromide（DTAB）compound system,the effects of mixing ratio and temperature on the aggregation behavior of the system and the effects of polymer type on the surfactant/polymer interaction were investigated by the method of conductivity and isothermal titration microcalorimetry（ITC）method.The results show that as the temperature increases,the CMC values of different compound systems first increase and then decrease,and the interaction strength between different polymers and compound systems is different,and there may only be nonionic surfactants and polymers.A weak interaction occurs,but the interaction between them can be improved by compounding with other surfactants.Finally,the interaction between the long-chain ionic liquid of1-methyl-3-tetradecylimidazole bromide(C₁₄mim Br)and five polymers was studied by means of surface tension,conductivity,isothermal titration microcalorimetry（ITC）and steady-state fluorescence methods,the effect of polymer concentration and type on the surfactant-polymer interaction is studied in detail.The results show that the interacting intensity between C₁₄mim Br and the polymer has the order of Na CMC>L64>F68>PVA>PEG,and as the concentration of the polymer increases,the strength of the interaction between the polymer and the surfactant increases,showing an excellent synergistic effect between the polymer and the surfactant.