Preparation And Characterization Of Gemini-Dipeptide Supramolecular Gelator

Supramolecular gel is a special kind of functional soft materials based on the non-covalent interactions.It has huge prospects in sensors,life medicine,environmental science and other fields.In this paper,the gemini valine dipeptide derivatives supramolecular gelators were prepared and studied in detail on the solvent gelling ability,self-assembly morphology and application in drug delivery.The main results and conclusions of this paper are summarized as follows:1.Gemini supramolecular gelators dodecamethylene-1,12-bis(N-(N-(4-pyridylmethyl-L-valyl))-L-valine)(DMPV)and dodecamethylene-1,12-bis(N-(N-(phenylmethyl-L-valyl))-L-valine(DMBV)based on 1,12-bis(N-(6-pyridiumhexanoyl)-L-valine)dibromide,N-(4-Pyridylmethyl)-L-valine and N-(Benzyl)-L-valine were prepared via the condensation coupling process.The gelators were characterized by FT-IR,1H NMR,UV-Vis and CD for the confirmation of structure,and FE-SEM,TEM,XRD and rheological measurements were conducted for the investigation of the different self-assemblies of the gelators in different solvents.Flory-Huggins parameters were calculated to estimate the interactions between DMPV and solvents,and it could serve as a model to predict the gelation behavior of DMPV in a range of mixture solvents.The results indicated that gelation occurred when the gelator-solvent interaction was neither too strong nor too weak,otherwise it would be solution or precipitate.The water-soluble stimulants,ceftiofur sodium and methylene blue could be in situ loaded into the gels and slowly released.2.DMPV exhibits remarkable changes in appearance during the transformation of gel-sol-gel and transforms into a transparent gel from opaque gel.These two forms of gel have been thoroughly investigated using polarizing microscope(POM),SEM,TEM,XRD,FT-IR and rheometric analyses.Moreover,rheological studies of these two gels reveal that transparent gel is stiffer than the opaque gel.3.2D layered materials with advantageous properties of metal-free,non-toxicity,stability and low-cost have attracted lots of attentions.g-C3N4 nanospheres were prepared using nanostructure silica as the hard template,and g-C3N4 nanosheets were prepared by hydrothermal method.Both of them were then characterized by XRD,SEM,and TEM.4.A facile and straightforward approach was used to prepare DMBV/g-C3N4 composite gels.The morphologies of DMBV/g-C3N4 gels could be controlled by adjusting the morphology of g-C3N4.It would and provid an evidence for the self-assembly of g-C3N4 and enrich the self-assemble theory of it.DMBV/g-C3N4 composite gels could be further used for controlled release of drugs due to its well-controlled releasing ability.