作　　者： ; ; ; ; ;

机构地区： 华南理工大学

出　　处： 《华南理工大学学报（自然科学版）》 2012年第7期123-127,154,共6页

摘　　要： 采用阳离子型芘荧光探针芘甲胺基盐酸盐跟踪聚N-异丙基丙烯酰胺(PNIPAm)/锂藻土Laponite原位聚合制备纳米复合水凝胶的过程.首先通过提高Laponite分散液的离子强度,采用离心分离和紫外-可见光吸收光谱验证了荧光探针在Laponite片层上的吸附;然后通过跟踪吸附荧光探针的激基缔合物的荧光光谱,发现反应液在聚合反应开始20min后出现的乳白色不透明现象与体系中形成的PNIPAm链的不均匀分布相关.聚合生成的高分子链吸附在Laponite片层周围,占据了片层上一定的空间,使得吸附在Laponite片层上的荧光分子被挤压而靠近,造成荧光激基缔合物的出现,因此可以通过荧光光谱变化来推测纳米复合(NC)凝胶聚合过程中透光率的变化及生成的聚合物链与交联剂Laponite之间的相互作用,这为深入认识NC凝胶的交联结构提供了一种实验方法. Cationic pyrene fluorescence probe 1-pyrenemethylamine hydrochloride （PyMA . HCl） was used to monitor the gelation of poly （N-isopropylacrylamide） （PNIPAm）/hectorite Laponite nanocomposite hydrogel via the insitu polymerization. First, the adsorption of PyMA . HCl on Laponite platelets was verified with UV-Vis spectra after aggregation and centrifuge by increasing the ionic strength of Laponite suspension. The results of fluorescence emission of excimer show that the milky nontransparent drops appear after a 20 min polymerization are related to the heterogeneous distribution of synthesized PNIPAm chains. Moreover, it is found that, as polymer chains are ad- sorbed around Laponite platelets and occupy part of platelet space, which shortens the distance between the fluores- cence probes on Laponite platelets and results in the formation of the excimer, both the change of transmittance du- ring the polymerization and the interaction between polymer chains and Laponite platelets can be determined according to fluorescence spectra. This finding provides an effective method to explore the crosslinking structure of nanocomposite hydrogels.

关 键 词： 锂藻土 纳米复合水凝胶 荧光 凝胶化

领　　域： [理学] [理学] [理学] [理学]