Preparation And Properties Of Supramolecular Hydrogels Based On Phenanthroline Or Nicotinamide

Supramolecular hydrogels have great application prospects in many fields such as medical,electronics,and environment.Among them,two-component supramolecular hydrogels have outstanding performance controllability and environmental sensitivity,so they have attracted much attention.Based on the existing research,the use of small molecules with simple structures to design and develop two-component supramolecular hydrogels with application value in the fields of drug sustained release and ion recognition will become an important research direction.Four common small molecules,namely 1,10-Phenanthroline(M),Pyromellitic acid(P),Nicotinamide(N),and Gallic acid(G),were used to design and prepare three kinds of two-component supramolecular hydrogels system(MP gel system,PN gel system,GN gel system).We used SEM,FT-IR,XRD and DSC to test the structure,gelation mechanism and basic properties of the three gels.The gel-response behavior of PN system gel under various environmental stimuli such as temperature,p H and ions was explored.At the same time,the application potential of GN system gel as a carrier in the field of drug sustained release was also explored.The main contents of the experiment are as follows:(1)M and P formed a white two-component supramolecular hydrogel in water at a molar ratio of 2:1.The research results show that M and P form a supramolecular polymer by self-assembly through intermolecular hydrogen bonding.Under the SEM,a rod-like fibrous structure is presented,and then the structure aggregates and binds a large number of water molecules,thereby forming a two-component supramolecular hydrogel.MP gel has good thermal reversibility and gel stability.According to the rheological test results,the gel exhibits a frequency-independent storage modulus and loss modulus at low frequencies,and has the rheological properties of a typical gel.In addition,research has found that gel molecule concentration and gel cooling rate can affect the state of water in the gel and its relative content,which can significantly affect the performance of the gel.(2)P and N can form white two-component supramolecular hydrogels in water at a molar ratio of 1:2 and 1:3,respectively.The results show that the gel system is mainly formed by the double non-covalent bond of intermolecular hydrogen bonding andπ-πstacking,and has good thermal reversibility,gel stability and rheological properties of typical gels.At the same time,the basic properties of the PN system gel can be adjusted by adjusting the ratio between the two components.In addition,due to the two-component group characteristics,the gel system is not only reversible to temperature and p H,but also has stimulus response to the halogen element F~-,which has potential application value in the fields of sensors and ion recognition.(3)G and N can form white two-component supramolecular hydrogels in water at a molar ratio of 1:1 and 1:2,respectively.The research results show that the gel system is also formed under the action of double non-covalent bonds of intermolecular hydrogen bonding andπ-πstacking,and has good thermal reversibility,gel stability and rheological properties of typical gels.The difference in the ratio of the gel components will not only bring about differences in gel properties,but also significantly affect the microstructure of the gel.In addition,GN12 gel in vitro drug sustained release experiments show that the gel has the ability to serve as a drug sustained-release drug-loading matrix and has certain potential in the field of drug sustained-release.