Department of Chemistry, Renmin University of China, 100872 Beijing, China.
Small. 2013 Jan 28;9(2):322-9. doi: 10.1002/smll.201201504. Epub 2012 Oct 9.
Block-copolymer (BCP) nanospheres with hierarchical inner structure are of great interest and importance due to their possible applications in nanotechnology and biomedical engineering. Mesoporous BCP nanospheres with multilayered inner channels are considered as potential drug-delivery systems and templates for multifunctional nanomaterials. Selective swelling is a facile pore-making strategy for BCP materials. Herein, the selective swelling-induced reconstruction of BCP nanospheres is reported. Two poly(styrene-block-2-vinylpyridine) (PS-b-P2VP) samples with different compositions (PS(23600)-b-P2VP(10400) and PS(27700)-b-P2VP(4300)) are used as model systems. The swelling reconstruction of PS-b-P2VP in ethanol, 1-pyrenebutyric acid (PBA)/ethanol, or HCl/ethanol (pH = 2.61) is characterized by scanning electron microscopy and transmission electron microscopy. It is observed that the length of the swellable block in BCP is a critical factor in determining the behavior and nanostructures of mesoporous BCP nanospheres in selective swelling. Moreover, it is demonstrated that the addition of PBA modifies the swelling structure of PS(23600)-b-P2VP(10400) through the interaction between PBA and P2VP blocks, which results in BCP nanospheres with patterned pores of controllable size. The patterned pores can be reversibly closed by annealing the mesoporous BCP nanospheres in different selective solvents. The controllable and reversible open/closed reconstruction of BCP nanospheres can be used to enclose functional nanoparticles or drugs inside the nanospheres. These mesoporous BCP nanospheres are further decorated with gold nanoparticles by UV photoreduction. The enlarged decoration area in mesoporous BCP nanospheres will enhance their activity and sensitivity as a catalyst and electrochemical sensor.
具有分级内部结构的嵌段共聚物（BCP）纳米球由于其在纳米技术和生物医学工程中的潜在应用而受到极大关注。具有多层内部通道的介孔 BCP 纳米球被认为是潜在的药物输送系统和多功能纳米材料的模板。选择性溶胀是 BCP 材料的一种简便的造孔策略。本文报道了通过选择性溶胀诱导 BCP 纳米球的重构。使用两种不同组成的聚（苯乙烯嵌段-2-乙烯基吡啶）（PS-b-P2VP）样品作为模型体系：PS(23600)-b-P2VP(10400)和 PS(27700)-b-P2VP(4300)。通过扫描电子显微镜和透射电子显微镜对 PS-b-P2VP 在乙醇、1-芘丁酸（PBA）/乙醇或 HCl/乙醇（pH = 2.61）中的溶胀重构进行了表征。结果表明，在选择性溶胀中，BCP 中可溶胀嵌段的长度是决定介孔 BCP 纳米球的行为和纳米结构的关键因素。此外，还证明了 PBA 的添加通过 PBA 和 P2VP 嵌段之间的相互作用来修饰 PS(23600)-b-P2VP(10400)的溶胀结构，从而得到具有可控制尺寸图案化孔的 BCP 纳米球。通过将介孔 BCP 纳米球在不同的选择性溶剂中退火，可以使图案化孔可逆地闭合。BCP 纳米球的可控且可重复的开/闭重构可用于将功能纳米粒子或药物包封在纳米球内部。进一步通过紫外光还原法将这些介孔 BCP 纳米球用金纳米粒子进行修饰。介孔 BCP 纳米球中增大的修饰面积将增强其作为催化剂和电化学传感器的活性和灵敏度。
