Preparation,Gelation Behavior And Application Of Multi-headgroup Surfactants

With the increasing of science and technology,It is put forward higher requirements for the cost and performance of surfactants,so scientists have developed a large number of novel surfactants to meet the needs of industry and science.The multi headgroup surfactants have unique aggregation structures due to their hydrophilic polar groups,and there are a wide range of applications in daily life,such as drug carriers,tertiary oil production,cosmetics and so on.Therefore,it is very important to study the physical and chemical properties of their interface behavior and aggregation behavior.Therefore,this paper designed and synthesized three kinds of multi headgroup surfactants with diacrylic acid as the headgroup,and studied their aggregation behavior in dilute solution.There are a lot of applications for the molecular gel in the nano-materials,chemical sensors,drug release,dye-sensitized solar batteries.Therefore,we used multi headgroup surfactants to form multi-responsive hydrogels to expand their applications,and explored their inherent gel mechanism,the specific work is as follows:1.Three synthetic dendritic surfactants were constructed with diacrylic acid as the headgroup.It was found that the three dendritic surfactants could form vesicle structure in dilute solution,and with the decrease of pH,The size of the vesicles will increase.Due to the decrease of pH,it will correspondingly increase for the degree of protonation of carboxyl groups,and it will be reduced for headgroup area of the surfactant.Thus the critical accumulation parameters were affected to achieve regulation of vesicle size.The formation and stability of vesicles were discussed by the critical accumulation parameters,spontaneous curvature,and bending moduli.There is great significance for pH-controlled vesicle size in the nano-science,biology,medicine and many other fields.2.The hydrogel of thermo-induced gel-to-gel was constructed from the dendritic zwitterionic surfactant C18 ADPA as a gelator.An opaque hydrogel at 25°C to a transparent hydrogel at 50°C.In the process of phase transition,the DSC test showed that the phase transition temperature was 43.3℃ during the hydrogel transition.The SEM and TEM studies showed that the network structure of the gel in this process changes from the branch nanotube to the lamellar structure,which is actually the phase transition of the bilayer structure to the worm-like micelles.C18 ADPA multi headgroup surfactants establish a multi responsive hydrogel system.It opens up a new method for the wide application of multi headgroup surfactants.3.Multiple responsive hydrogel was successfully formed with C18 ADPA as gelator by the addition of Fe²⁺.During the oxidation of Fe²⁺ into Fe³⁺ by H₂O₂,the gel-sol transition was realized.TEM and XRD results showed that the microstructure of the gel changed from nanoribbons to vesicle structure,and IR indicated that COO-coordinated with metal ions by monodentate coordination.After carbonation at 600°C,porous carbon hard material was obtained from the soft material.Electrochemical performance studies showed that the material had a high specific capacitance,and charge-discharge reversibility.The significance of this work that porous carbon hard material was prepared by carbonating hydrogel soft material.And it provides a new method to prepare porous materials.