Continuous laminar flow microreactors for the synthesis of spindle-like ZnO materials. (A) Schematic diagram of the growth and assembly of ZnO tactoids in a continuous flow microreactor. Reproduced with permissions from reference55, copyright 2013, Royal Society of Chemistry. (B) PDMS-based microreactor for the synthesis of ZnO spindles. Reproduced with permissions from reference75, copyright 2017, IOP Publishing, Ltd. (C) Experimental setup used for the continuous preparation of Ag–ZnO nanohedgehog. Reproduced with permissions from reference69, copyright 2016, Royal Society of Chemistry.