School of Chemical Engineering, Sichuan University, Chengdu, Sichuan 610065, China.
J Colloid Interface Sci. 2010 Sep 15;349(2):512-8. doi: 10.1016/j.jcis.2010.05.084. Epub 2010 May 31.
Smart responsive microcapsules capable of recognizing heavy metal ions are successfully prepared with oil-in-water-in-oil double emulsions as templates for polymerization in this study. The microcapsules are featured with thin poly(N-isopropylacrylamide-co-benzo-18-crown-6-acrylamide) (P(NIPAM-co-BCAm)) membranes, and they can selectively recognize special heavy metal ions such as barium(II) or lead(II) ions very well due to the "host-guest" complexation between the BCAm receptors and barium(II) or lead(II) ions. The stable BCAm/Ba(2+) or BCAm/Pb(2+) complexes in the P(NIPAM-co-BCAm) membrane cause a positive shift of the volume phase transition temperature of the crosslinked P(NIPAM-co-BCAm) hydrogel to a higher temperature, and the repulsion among the charged BCAm/Ba(2+) or BCAm/Pb(2+) complexes and the osmotic pressure within the P(NIPAM-co-BCAm) membranes result in the swelling of microcapsules. Induced by recognizing barium(II) or lead(II) ions, the prepared microcapsules with P(NIPAM-co-BCAm) membranes exhibit isothermal and significant swelling not only in outer and inner diameters but also in the membrane thickness. The proposed microcapsules in this study are highly attractive for developing smart sensors and/or carriers for detection and/or elimination of heavy metal ions.
本研究成功制备了智能响应微胶囊，该微胶囊能够识别重金属离子，是以油包水包油（O/W/O）双重乳液作为聚合模板。微胶囊具有薄的聚（N-异丙基丙烯酰胺-co-苯并-18-冠-6-丙烯酰胺）（P（NIPAM-co-BCAm））膜，由于 BCAm 受体与钡（II）或铅（II）离子之间的“主客体”络合作用，它们可以很好地选择性识别特殊的重金属离子，如钡（II）或铅（II）离子。P（NIPAM-co-BCAm）膜中稳定的 BCAm/Ba（2+）或 BCAm/Pb（2+）配合物会使交联的 P（NIPAM-co-BCAm）水凝胶的体积相转变温度向更高温度发生正移，带电荷的 BCAm/Ba（2+）或 BCAm/Pb（2+）配合物之间的斥力和 P（NIPAM-co-BCAm）膜内的渗透压会导致微胶囊的膨胀。通过识别钡（II）或铅（II）离子，制备的具有 P（NIPAM-co-BCAm）膜的微胶囊不仅在外径和内径，而且在膜厚度上都表现出等温且显著的溶胀。本研究中提出的微胶囊非常适合开发用于检测和/或消除重金属离子的智能传感器和/或载体。
