The present invention generally relates to microfluidics, and to spray drying and other drying techniques. By at least partially drying fluids within a microfluidic channel, instead of or in addition to conventional spray drying techniques, better control of the drying process can be achieved in certain aspects of the invention. In addition, various embodiments of the invention are generally directed to systems and methods for drying fluids contained within a channel such as a microfluidic channel. For example, a fluid may be partially or completely dried within a microfluidic channel, prior to being sprayed into a collection region. In some embodiments, gases such as air may be directed into a channel containing a fluid, which may facilitate drying of the fluid. In some cases, the fluid may be accelerated due to the introduction of gases into the channel, and in certain embodiments, droplets of fluid may be disrupted to form smaller droplets as a result. In certain cases, the fluids may also be dried to form supersaturated droplets.