Droplet microfluidics have made tremendous progress in the last two decades in the generation of micrometer- and nanometer-scale materials. One of the major developments lies in the incorporation of multiple microfluidic devices onto single chips enabling emulsion generation at clinical and industrial-relevant scale. However, most demonstrated successes have focused on producing simple emulsions; production upscaling of complex emulsion and materials have not been realized. In this thesis, I will demonstrate new approaches and some early successes to fill this gap between lab-scale and industrially relevant scale production of complex emulsion and drop-based on-chip material synthesis. First, a silicon-and-glass based microchip is developed for ultrahigh throughput on-chip photopolymerization of microgels. We demonstrate that the mechanical properties of microgels can be modulated by tuning the UV dosage and reached a throughput >1kg/hr with a massive parallelization of 4080 microfluidic synthesis lines on a 4-inch wafer. The masking strategy is a key innovation that enables on-chip gelation with parallelization architecture. We believe this platform is a major step toward clinical applications of precise and highly uniform microgels and shows on-chip multistep synthesis provides advantages that are unachievable by off-chip synthesis. Spatial patterning of wetting properties on the microfluidic channels is essential for the successful generation and stability of multiple emulsions. However, existing patterning techniques have proven to be challenging to be adapted for complex microfluidic architectures. To address this challenge, we develop a new fabrication process to pattern the hydrophobicity of a silicon-based microfluidic chip, taking advantage of photolithography and silane chemistry. We demonstrate wettability patterning with micrometer resolution and generation of both W/O/W and O/W/O double emulsions. Further, the scalability of this approach is demonstrated with chips that incorporate 50 parallelized double-emulsion generating devices, producing double emulsions in a high throughput manner (26.5 kHz double emulsions). Lastly, I extend the above approach and develop a novel approach to perform surface wettability patterning via polymer enrichment and replica molding (SUPER), controlling the wettability of microfluidic channels made of a solvent resistant PFPE-PEG copolymer network. In this approach, the mold is a silicon wafer with lithographically defined features etched into its surface to define channel geometry and lithographically defined patterns of hydrophobic silanes to define surface wetting properties. The replica is a co-polymer network of PFPE-PEG, for which PFPE can be locally enriched by hydrophobicity of the mold to define the spatially patterned wetting properties. We demonstrate the utility of this approach by fabricating a PFPE-PEG based microfluidic chip, with hydrophobic/hydrophilic patterned microchannels, to generate double emulsions.