"This proposal aims to establish a novel type of kinetic experiment by combining microfluidics with micro-x-ray technology to develop a fundamental understanding of nucleation and growth of organic and inorganic nanoparticles, thus aiming to help producing these particles more efficiently in times of constraint materials resources.The methodology maps particle growth kinetics form the time- to the length scale. The proposed combination with microbeam x-ray diffraction extends the temporal resolution, determined by the spot-size of the microbeam, into the microsecond regime. This enables to elucidate nanoparticle nucleation and growth from early nucleation states to late growth states during which the shape of the particles is decided, thus opening pathways to new particle morphologies and improving existing synthetic procedures.The method is applied to the investigation of amphiphile self-assembly kinetics, inorganic nanocrystal growth and ultrafast polymer nanoparticle formation, where any improvement in the understanding of the growth mechanism is expected to directly lead to a more rational design of the synthesis, extending the range of morphologies and applications.That way, it is expected that STREAM can clarify particle nucleation and growth to expand the possibilities of nanoparticle synthesis to provide new and better materials for energy, information and medical technology."