Microfluidic Fabrication of Morphology-Controlled Polymeric Microspheres of Blends of Poly(4-butyltriphenylamine) and Poly(methyl methacrylate)

Abstract

Multicomponent polymer particles with specific morphology are promising materials exhibiting novel functionality which cannot be obtained with single-component polymer particles. Particularly, the preparation of such kinds of polymer particles involving electrically or optically active conjugated polymers with uniform size is a challenging subject due to their intense demands. Here, microspheres of binary polymer blend consisting of poly(4-butyltriphenylamine) (PBTPA)/poly(methyl methacrylate) (PMMA) (1:1 in weight) were produced via a microfluidic emulsification with a Y-shaped microreactor, and a subsequent solvent evaporation method. The flow rate of the dispersed phase (polymer solution) was fixed to 7 µL/min, and 140 or 700 µL/min of the flow rate of the continuous phase (aqueous 0.6 wt % of poly(vinyl alcohol) (PVA) solution) was utilized to produce the dispersion with different diameter. The concentration of dispersed phase was adjusted to 0.1 or 1.0 w/v%. Core-shell, Janus and dumbbell type microspheres were obtained dependent on the flow rate of continuous phase. Incomplete core-shell type microspheres were produced for the blend involving low molecular weight PMMA. Complex Janus and core-shell type microspheres were fabricated by the addition of sodium dodecyl sulfate (SDS) to continuous phase. It is found that final morphologies are strongly dependent on the initial conditions of dispersion including the particle size suggesting that the morphologies are governed by the kinetical factors together with the conventionally accepted thermodynamic ones.

Precision Polymer Particles by Flash Nanoprecipitation and Microfluidic Droplet Extraction

“…Other polymer/BCP mixtures offer opportunities to generate unique particle structures; Zhu et al reported that addition of poly­(styrene)- b -poly­(ethylene oxide) (PS- b -PEO) to PS/chloroform droplets yielded foam-like, nodular (vesicular) and spiky microparticles following solvent extraction. Varying the solvent removal rate and composition of droplets from mixtures of poly­(4-butyltriphenylamine) (PBTPA), poly­(methyl methacrylate) (PMMA), and poly­(4-butyltriphenylamine)- b -poly­(methyl methacrylate) (PBTPA- b -PMMA) has been shown to generate a range of spherical, core–shell, Janus, and internally phase-separated particle structures. , …”

“…The lowest energy structures are not necessarily determined by minimization of interfacial energies and therefore are not always spherical; mechanical instabilities can occur, triggered by the compressive stresses occurring during internal volume reduction of a soft-solid or viscoelastic skin, or gradient multilayered profile, and resulting in folding, buckling, irregular polyhedral, and higher aspect ratio shape formation, illustrated in Figure , parts f and g, or even completely collapsed and crumpled particles . Further modulation can be achieved by doping with colloids into the polymer solution droplets, driving more complex thermodynamic and mechanic pathways, and can result in a variety of bicontinuous structures encapsulating colloidal clusters and external particle shapes, shown in Figure h. , With added components such as BCPs, the kinetics and thermodynamics of self-assembly, interfacial stabilization and spatial segregation of individual species within multicomponent droplets during drying give rise to a wide range of complex, hierarchical and (often) anisotropic particle structures. , Ku et al have comprehensively reviewed the topic of BCP particles. Here, we highlight two such structures based on polymer/BCP blends where the self-assembly of BCPs during drying-induced interfacial instabilities lead to striking particle morphologies, as seen in the nodular (“budding vesicular”) and spiky particle structures in Figure , parts i and j …”

“…Varying the solvent removal rate and composition of droplets from mixtures of poly(4-butyltriphenylamine) (PBTPA), poly(methyl methacrylate) (PMMA), and poly(4butyltriphenylamine)-b-poly(methyl methacrylate) (PBTPA-b-PMMA) has been shown to generate a range of spherical, core−shell, Janus, and internally phase-separated particle structures. 169,170 Higher order microfluidic droplets have also been exploited to template microparticles via DSE. Hollow and core−shell polymer microcapsules have also been generated employing W/O/W double emulsion droplets with the polymer dissolved in the middle oil phase; ethyl cellulose (EC) dissolved in EA, 161 PLA in DCM or chloroform or chloroform:toluene mixtures 157,171,172 and PS in toluene.…”

Diverse Particle Carriers Prepared by Co‐Precipitation and Phase Separation: Formation and Applications

“…argued that the effect of molecular weight on the mobility of the polymer also plays an important role in determining the particle morphology. Reducing the molecular weight of PMMA in the dispersed phase accelerates the translational speed of the PMMA‐rich phase and enables the engulfing of PBTPA polymer by PMMA polymer, which changes its morphology from an spherical Janus structure to an incomplete core‐shell structure, as shown in Figure 2d [32] …”

Surface Modification of Poly(lactic-co-glycolic acid) Microspheres with Enhanced Hydrophilicity and Dispersibility for Arterial Embolization

“…Functional polymeric microspheres, which are often used in chemical catalysis and adsorption, have some special advantages, including a large specific surface area, strong adsorption capacity, surface reaction ability, and ease of modification [1,2], tumor embolization [3,4], information transfer [5], chromatographic separation [6], and biomedicine [7]. Transcatheter arterial embolization (TAE) was first reported by Yamamoto et al [8] in 1991, which was an effective technique for the insertion of a catheter into a target tissue or organ.…”