In situ microfluidic fabrication of multi-shape inorganic/organic hybrid particles with controllable surface texture and porous internal structure

Abstract

In this study, multiple shapes like spherical, ellipsoidal, disk-like, and rod-like inorganic/organic hybrid particles are fabricated using droplet-based microfluidics. Instead of photo-polymerization, which is commonly used in previously reported studies, the diversity in particle configuration is realized via the fast hydrolysis of an organometallic compound. In comparison to inorganic/organic hybrid particles fabricated by directly incorporating inorganic components in the dispersed phase before droplet formation, our hybrid particles are synthesized in situ because the inorganic component is one of the hydrolysis products, which avoids the agglomeration or precipitation of inorganic components and thus ensures particle homogeneity. In this study, we demonstrate a new strategy by using hybrid particle containing poly (lactide-co-glycolide) (PLGA) and TiO₂ as a model material, among which TiO₂ is obtained from the hydrolysis of n-butyl titanate (TBT). The convoluted surface texture of PLGA/TiO₂ particles can be attributed to either the interfacial instabilities of droplets induced by n-butanol as the other hydrolysis product, or the elastic-driven wrinkling of the solid film generated on PLGA/TBT droplet surfaces through TBT hydrolysis. Moreover, due to the presence of hyper-dispersed n-butanol caused by localized TBT hydrolysis in the PLGA matrix, a porous internal structure can be formed in the PLGA/TiO₂ particle. We believe this strategy is versatile to fabricate numerous types of inorganic/organic hybrid particles, among which partial or all components can be synthesized through the quick hydrolysis of organometallic compounds.