Online detection and automation methods in microfluidic nanomaterial synthesis

•Online analysis of nanoparticles in microfluidic reactors.•Nanoparticle synthesis in microreactors.•Automation methods for microfluidic nanoparticle synthesis.

Microfluidic reactors are increasingly being recognized as a promising tool for the synthesis of bespoke and high quality nanomaterials. Herein, we discuss currently available methods for interfacing microfluidic reactors with online analysis systems such as photothermal, fluorescence, absorbance, X-ray, backscattering and correlation spectroscopies. Integration of appropriate on-line detection methods enables the facile extraction of information relating to size, shape and chemical composition of the formed nanoparticles, thus greatly enhancing control over the synthetic process. Furthermore, we discuss recent approaches aimed at implementing ‘intelligent’ algorithms that use such extracted information for optimization and parameter space evaluation. Lastly, we provide brief opinion about future directions of this emerging field.