作者：Wenjun Gao, Qingsong Zhang
关键字：hydrogel,template,temperature,pore
论文来源：期刊
具体来源：RSC Advances
发表时间：2014年
To investigate the change upon structure and temperature-sensitivity of porous hydrogel before and after removing template and confirm the pore formation mechanism, a series of hydrogels (abbreviated as CLH) based on N-isopropylacrylamide (NIPAM) serving as functional monomer and polyoxyethylene-20-cetyl-ether (Brij-58) acting as template were obtained. The chemical composition, crystal structure and temperature-sensitivity of PNIPAM hydrogels before and after template were compared and confirmed by FTIR, XRD and DSC. The optical performance, pore shape and (de)swelling behavior of prepared CLH hydrogels were investigated by UV/vis, SEM and gravimetric method. The disappearance of characteristic absorption peak at 1062-1146 cm^?1 and coincidental absorption peak at 195nm, and recovery of diffraction peak at 2θ = 7.8° and 2θ = 20.75° all confirmed that Brij-58 plays a template action and could be removed after 48h. With increasing mass ratios of Brij-58/NIPAM from 0 to 2, the critical time of optical transmittance of CLH hydrogels dropping to 0 from 100 decreases to 7.5 min from 22 min, while maximum equilibrium swelling ratios increase from 6.3 to10.31g/g. SEM graphs show that, with increasing mass ratios of Brij-58/NIPAM from 0 to 2, CLH hydrogels firstly form homogeneous and smaller pore, and then pore sizes increase from 4-10μm to 50-100μm together with interconnected pore structure. With increasing mass ratios of Brij-58/NIPAM, thermo-responsibility of CLH hydrogels containing Brij-58 template disappeared gradually and then recovered after removing template. The deswelling rates of CLH hydrogels depend on the mass ratios of Brij-58/NIPAM, as r=Brij-58/NIPAM≤1/10, the hydrogels lose over 70% water within 60min, while the hydrogel loses over 70% water within 10min as r=Brij-58/NIPAM=2. This kind of templated hydrogel with adjustable porous structure has much potential in the fields of drug delivery system, tissue engineering and chemical separation.