单步溶胀聚合法制备单分散分子印迹聚合物微球

Preparation of Monodisperse Molecularly Imprinted Polymer Beads by a Single-Step Swelling and Polymerization Method

用无皂乳液聚合法制备了微米级粒径均匀的聚苯乙烯微球(PS)。以制得的PS为种球,柚皮素为模板分子,通过单步溶胀聚合法制备了单分散分子印迹聚合物微球(MIPBs)。研究了溶胀比及环己醇用量对MIPBs粒径及形态的影响,结果发现,采用粒径为1.50μm的PS作种球,且溶胀比控制在27~60时,可以制得粒径在4.5μm^6.0μm单分散的MIPBs;随着环己醇用量的增大,MIPBs球形更加规则、表面更加光滑。氮气吸附测量结果表明,制得的MIPBs是一种具有多孔结构、比表面积大的聚合物。Scatchard分析结果表明,在研究的浓度范围内,MIPBs存在一类等同的结合位点,其平衡离解常数Kd和最大表观吸附量Qmax分别为8.61mmol·L-1和48.50μmol·g-1。制得的MIPBs对模板化合物柚皮素显示出较高的选择性,以槲皮素为竞争底物,其分离因子达1.96。

Uniformly sized polystyrene particles （PS） with diameters of micrometer class were prepared by emulsifier-free polymerization. Using the prepared PS as seeds, naringenin as template molecules, monodisperse molecularly imprinted polymer beads （MIPBs） were prepared by a single-step swelling and polymerization method. The effects of swelling ratio and the dosage of assistant porogen--cyclohexanol on particle size and morphology of the MIPBs were investaged. It is found that the monodisperse MIPBs with particle diameters of 4.5-6.0μm can be obtained by using 1.50μm PS prepared as seed and controlling the swelling ratio in the range of 27-60. With the increase of cyclohexanol dosage used, the spheroidicity of the MIPBs prepared becomes more regular and its surface tends to be smoother. The results of nitrogen adsorption measurements show that the MIPBs have porous structure and large specific area. Scatchard analysis shows that the binding sites of equal class are formed in the MIPBs under the concentration range studied, and the dissociation constant Kd and maximum apparent adsorption quantity Qmax of these binding sites are 8.61 mmol·L^-1 and 48.50 μmol·g^-1, respectively. The MIPBs exhibit high selectivity for naringenin, and the separation factor is up to 1.96 when quercetin is chosen as the competitive molecules.