The Study On P-M Two-component Gelator

Two-component gelators of Organophosphorus acid or organic phosphonic acid(P) and melamine derivatives (M) have been designed and prepared. Studies ongelation ability, mechanism of gelation, gel thermal stability and effect of gelatorstructure on gelation performance are intensified. Exploratory works on monoalkylphosphate esters ability have also been studied.In two-component system, the gelation ability are found to be very dependenton a slight difference of one component, among the12gelators prepared, C2, D2, A3and D3have the best gelation performance. The hydrogen bond of solvents havecompetitive interactions preventing the establishment of gelator-gelator hydrogenbonding networks and polar solubility parameter (δa) plays a key role in determiningthe morphologies of aggregates, the sol-gel phase-transition temperature (Tgel) and thegelation number (Ngel), but other properties of solvents, such asolvent molecular sizeand density of solvent, may also have effect on gelation abilities..The research of gelation performance of two-component gelator in mixedsolvent reveals that: gelator A2was soluble in methanol and insoluble in water.However it could form opaque gels at a certain water volume fraction inmethanol-water mixtures. The microstructure of xerogel, minimum gelationconcentrations, thermal stabilities of the gels and molecular packing modes of A2intheir gel networks are found to be very dependent on the composition of the mixedsolvents. Flory-Huggins parameters were used to study the gelator-solvent interactionand explain the gelation test in different mixed-solvents.Sodium monododecyl phosphate (MDP-Na) could not form a gel in water.Addition of NaCl to the aqueous medium promotes the gelation and also caused theminimum gelation concentrations decreased. XRD results showed that with theaddition of NaCl the hydrogel had a hexagonal structure compared to the layeredstructure in precipitate. Acetoguanamine-monododecyl phosphate (AMDP) couldform gels in water and alcohol. For the alcohol gels, polar solubility parameter (δa)plays a key role in determining the sol-gel phase-transition temperature (Tgel) and thegelation number (Ngel). The addition of NaCl to AMDP hydrogel may cause thedecrease of thermal stabilities and mechanical properties.