Dynamic control of gold nanoparticle morphology in a microchannel flow reactor by glucose reduction in aqueous sodium hydroxide solution

► Continuous and environmentally benign synthesis of gold nanoparticles in a micro channel reactor. ► Dynamic color and spectral change by control of NaOH addition rate. ► Novel star like morphology as quasi stable intermediates transformed into round shape together with the spectral change. ► The series of color change was responsible to the relative number of star particles.