Das Anirban, Yadav Nitin, Manchala Saikumar, Bungla Manisha, Ganguli Ashok K
Department of Chemistry, Biochemistry and Forensic Sciences, Amity School of Applied Sciences, Amity University Haryana, Gurugram, Haryana 122413, India.
Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi, Delhi 110016, India.
ACS Omega. 2021 Jan 4;6(2):1007-1029. doi: 10.1021/acsomega.0c04033. eCollection 2021 Jan 19.
Tailoring the characteristics of anisotropic nanostructures like size, morphology, aspect ratio, and size dispersity is of extreme importance due to the unique and tunable properties including catalytic, optical, photocatalytic, magnetic, photochemical, electrochemical, photoelectrochemical, and several other physical properties. The reverse microemulsion (RM) method offers a useful soft-template and low-temperature procedure that, by variation of experimental conditions and nature of reagents, has proved to be extremely versatile in synthesis of nanostructures with tailored properties. Although many reports of synthesis of nanostructures by the RM method exist in the literature, most of the research studies carried out still follow the "hit and trial" method where the synthesis conditions, reagents, and other factors are varied and the resulting characteristics of the obtained nanostructures are justified on the basis of existing physical chemistry principles. Mechanistic investigations are scarce to generate a set of empirical rules that would aid in preplanning the RM-based synthesis of nanostructures with desired characteristics as well as make the process viable on an industrial scale. A consolidation of such research data available in the literature is essential for providing future directions in the field. In this perspective, we analyze the literature reports that have investigated the mechanistic aspects of growth of anisotropic nanostructures using the RM method and distil the essence of the present understanding at the nanoscale timescale using techniques like FCS and ultrafast spectroscopy in addition to routine techniques like DLS, fluorescence, TEM, etc.
由于各向异性纳米结构具有独特且可调节的性质，包括催化、光学、光催化、磁性、光化学、电化学、光电化学以及其他多种物理性质，因此定制其尺寸、形态、纵横比和尺寸分散性等特征极为重要。反相微乳液（RM）法提供了一种有用的软模板和低温制备方法，通过改变实验条件和试剂性质，已证明该方法在合成具有定制性质的纳米结构方面具有极高的通用性。尽管文献中有许多关于通过RM法合成纳米结构的报道，但大多数开展的研究仍遵循“反复试验”方法，即改变合成条件、试剂及其他因素，然后根据现有的物理化学原理来解释所得纳米结构的最终特征。目前缺乏机理研究来生成一套经验规则，以帮助预先规划基于RM法合成具有所需特征的纳米结构，并使该过程在工业规模上可行。整合文献中现有的此类研究数据对于为该领域提供未来方向至关重要。从这个角度出发，我们分析了那些研究使用RM法生长各向异性纳米结构机理方面的文献报道，并除了使用动态光散射（DLS）、荧光、透射电子显微镜（TEM）等常规技术外，还利用荧光相关光谱（FCS）和超快光谱等技术，在纳米尺度时间范围内提炼了当前认识的要点。
