School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332.
Faculty of Materials Science and Engineering, South China University of Technology, 510640 Guangzhou, China.
Proc Natl Acad Sci U S A. 2018 Feb 13;115(7):E1391-E1400. doi: 10.1073/pnas.1714748115. Epub 2018 Jan 31.
The ability to dynamically organize functional nanoparticles (NPs) via the use of environmental triggers (temperature, pH, light, or solvent polarity) opens up important perspectives for rapid and convenient construction of a rich variety of complex assemblies and materials with new structures and functionalities. Here, we report an unconventional strategy for crafting stable hairy NPs with light-enabled reversible and reliable self-assembly and tunable optical properties. Central to our strategy is to judiciously design amphiphilic star-like diblock copolymers comprising inner hydrophilic blocks and outer hydrophobic photoresponsive blocks as nanoreactors to direct the synthesis of monodisperse plasmonic NPs intimately and permanently capped with photoresponsive polymers. The size and shape of hairy NPs can be precisely tailored by modulating the length of inner hydrophilic block of star-like diblock copolymers. The perpetual anchoring of photoresponsive polymers on the NP surface renders the attractive feature of self-assembly and disassembly of NPs on demand using light of different wavelengths, as revealed by tunable surface plasmon resonance absorption of NPs and the reversible transformation of NPs between their dispersed and aggregated states. The dye encapsulation/release studies manifested that such photoresponsive NPs may be exploited as smart guest molecule nanocarriers. By extension, the star-like block copolymer strategy enables the crafting of a family of stable stimuli-responsive NPs (e.g., temperature- or pH-sensitive polymer-capped magnetic, ferroelectric, upconversion, or semiconducting NPs) and their assemblies for fundamental research in self-assembly and crystallization kinetics of NPs as well as potential applications in optics, optoelectronics, magnetic technologies, sensory materials and devices, catalysis, nanotechnology, and biotechnology.
通过使用环境触发（温度、pH 值、光或溶剂极性）来动态组织功能性纳米粒子（NPs）的能力为快速方便地构建具有新结构和功能的各种复杂组装体和材料开辟了重要的前景。在这里，我们报告了一种用于制造具有光响应性的稳定的发状纳米粒子的非常规策略，该策略具有可逆转和可靠的自组装以及可调谐的光学性能。我们策略的核心是巧妙设计包含亲水性内块和疏光响应性外块的两亲性星形嵌段共聚物作为纳米反应器，以指导单分散等离子体 NPs 的合成，这些 NPs 紧密且永久地被光响应性聚合物覆盖。通过调节星形嵌段共聚物中亲水性内块的长度，可以精确调整发状纳米粒子的尺寸和形状。光响应性聚合物在 NP 表面的永久锚定赋予了 NPs 按需自组装和解组装的吸引人的特性，这可以通过 NPs 的可调表面等离子体共振吸收和 NPs 在分散和聚集状态之间的可逆转变来揭示。染料包封/释放研究表明，这种光响应性 NPs 可用作智能客体分子纳米载体。通过扩展，星形嵌段共聚物策略使能够制造一系列稳定的刺激响应性 NPs（例如，温度或 pH 值敏感聚合物覆盖的磁性、铁电、上转换或半导体 NPs）及其组装体，用于 NPs 的自组装和结晶动力学的基础研究以及在光学、光电、磁技术、传感材料和器件、催化、纳米技术和生物技术中的潜在应用。
