Multifunctional colloids with optical, magnetic, and superhydrophobic properties derived from nucleophilic substitution-induced layer-by-layer assembly in organic media.
Multifunctional colloids with optical, magnetic, and superhydrophobic properties derived from nucleophilic substitution-induced layer-by-layer assembly in organic media.
复制标题
DOI：
10.1021/nn200538a
复制
发表时间：
2011-06
期刊：
影响因子：
17.1
通讯作者：
Miseon Yoon;Younghoon Kim;Jinhan Cho
中科院分区：
文献类型：
--
作者：
Miseon Yoon;Younghoon Kim;Jinhan Cho
我们展示了在有机介质中，基于溴和胺基团之间的亲核取代（NS）反应，使用层接层（LbL）组装，通过涂覆2-溴-2-甲基丙酸（BMPA）稳定的量子点（BMPA- qds）和BMPA稳定的氧化铁颗粒(BMPA- fe （3)O(4)）以及胺功能化的聚胺胺（PAMA）树状大分子，成功制备了多功能二氧化硅胶体。本研究中使用的量子点和Fe(3)O(4)纳米粒子是在非极性溶剂（氯甲烷或甲苯）中直接合成的，油酸稳定剂与BMPA在同一溶剂中交换，以减少对纳米粒子的化学和物理损伤。纳米粒子在有机溶剂中通过NS反应直接吸附，由于邻近纳米粒子之间不存在静电斥力，从而显著增加了纳米粒子在横向尺寸上的堆积密度。包覆纳米颗粒的多功能胶体在非极性溶剂中表现出优异的特性（超顺磁性、光致发光和磁光调谐性能）和长期稳定性。此外，将纳米复合胶体沉积在平面基底上，然后涂覆低表面能的氟烷基硅烷聚合物，在胶体膜中产生密集堆积的粗糙表面形态，显示出水接触角大于150°的超疏水性。
We demonstrate the successful preparation of multifunctional silica colloids by coating with 2-bromo-2-methylpropionic acid (BMPA)-stabilized quantum dots (BMPA-QDs) and BMPA-stabilized iron oxide particles (BMPA-Fe(3)O(4)), along with amine-functionalized poly(amidoamine) (PAMA) dendrimers, using layer-by-layer (LbL) assembly based on a nucleophilic substitution (NS) reaction between the bromo and amine groups in organic media. The QDs and Fe(3)O(4) nanoparticles used in this study were directly synthesized in a nonpolar solvent (chloroform or toluene), and the oleic acid stabilizers were exchanged with BMPA in the same solvent to minimize chemical and physical damage to the nanoparticles. The direct adsorption of nanoparticles via an NS reaction in organic solvent significantly increased the packing density of the nanoparticles in the lateral dimensions because electrostatic repulsion between neighboring nanoparticles was absent. The multifunctional colloids densely coated with nanoparticles showed excellent characteristics (i.e., superparamagnetism, photoluminescence, and magneto-optical tuning properties) with long-term stability in nonpolar solvents. Furthermore, deposition of the nanocomposite colloids onto flat substrates, followed by coating with a low-surface-energy fluoroalkylsilane polymer, produced a densely packed rugged surface morphology in the colloidal films that displayed superhydrophobic properties with water contact angles greater than 150°.