本文研究了一系列两阶段乳液聚合物薄膜的应力-应变行为。这些乳液聚合物藉在硅熔胶中预先制得的聚甲基丙烯酸甲酯(PMMA)存在下,由甲基丙烯酸甲酯(MMA),丙烯酸2-乙基已酯(EHA)和丙烯酸2-羟基乙酯(HEA)聚合而得。乳液颗粒的 TEM 显微照片说明共聚组分中含有的 HEA 可增强硅熔胶与乳液颗粒间的相互作用,因此能显著地改善相应乳液所成薄膜的力学性能。 相似文献
Colloidal core/shell nanocrystals contain at least two semiconductor materials in an onionlike structure. The possibility to tune the basic optical properties of the core nanocrystals, for example, their fluorescence wavelength, quantum yield, and lifetime, by growing an epitaxial‐type shell of another semiconductor has fueled significant progress on the chemical synthesis of these systems. In such core/shell nanocrystals, the shell provides a physical barrier between the optically active core and the surrounding medium, thus making the nanocrystals less sensitive to environmental changes, surface chemistry, and photo‐oxidation. The shell further provides an efficient passivation of the surface trap states, giving rise to a strongly enhanced fluorescence quantum yield. This effect is a fundamental prerequisite for the use of nanocrystals in applications such as biological labeling and light‐emitting devices, which rely on their emission properties. Focusing on recent advances, this Review discusses the fundamental properties and synthesis methods of core/shell and core/multiple shell structures of II–VI, IV–VI, and III–V semiconductors.
