Study On The Preparation And Chromatographic Performance Of Thermosensitive Monolithic Column

N-isopropylacrylamide (NIPAAm) hydrogel is one of the intensively studied thermosensitive hydrogels owing to the combination of hydrophilic amide groups and hydrophobic isopropyl groups within its macromolecule side-chain. Poly(N-isopropylacrylamide) (PNIPAAm) gel is a sort of non-ionic thermosensitive hydrogel. Derived from above-mentioned character, PNIPAAm has been of great interest for a wide variety of applications, for instance, devices for immobilization of enzymes, biomedicine, controlled drug release, super recyclable absorbents and chemical separation. However, conventional PNIPAAm hydrogels, prepared using single organic crosslinkers, have a few serious disadvantages such as brittle, the lack of mechanical strength and low swelling/deswelling rates, which often restricted in their applications severely.In this paper, a review concerned with the development of intelligent hydrogels during recent years was introduced firstly. The classification and characteristics of thermosensitive hydrogels were emphasized introduced. The current situation of the research towards PNIPAAm hydrogels and fast responsive thermosensitive PNIPAAm hydrogels was also reviewed. Moreover, the application overview of PNIPAAm hydrogels and fast responsive thermosensitive PNIPAAm hydrogels was for the domain such as biopharmaceutics and separation science was also described.Whereafter, fast responsive thermosensitive poly(N-isopropylacrylamide-co-co-N,N'-methylene-bisacrylamide) [poly(NIPAAm-co-BIS)] hydrogel monolith was prepared using N-isopropylacrylamide (NIPAAm) as monomer, N,N'-methylene-bisacrylamide (BIS) as crosslinker, ammonium persulfate (APS) and N,N,N',N'-tetramethylethylenediamine (TEMED) as initiator, polyethylene glycol (PEG) (10000,20000) as pore forming agent, water as solvent. The polymerization was finished by free radical cryo-polymerization using redox at-12℃. The effects of the crosslinking agent and pore-forming agent on temperature sensitive swelling properties and low critical solution temperature have been investigated.Finally, the crosslinker and pore-forming agent factors affecting the porous structure prosperities of hydrogel monolithic columns were investigated. Under the optimum condition, the monolith for HPLC was successfully prepared and its mechanical strength, permeability and chromatographic performance were studied. Furthermore, experimental results indicated that a column with temperature-dependent chromatographic resolution of medicine molecules was achieved using only water as mobile phase on aforementioned fast responsive thermosensitive hydrogel monolith.