Assembly of uniform photoluminescent microcomposites using a novel micro‐fluidic‐jet‐spray‐dryer

Abstract

Generation of uniform micro-particles containing (i) pure lactose; (ii) silica nanoparticles and lactose; (iii) silica nanoparticles/lactose doped with Eu(III) have been successfully achieved using a novel spray dryer with a uniquely designed microfluidic aerosol nozzle as the monodisperse droplet generator. Here we investigate the impacts of precursor compositions and concentrations, as well as the drying temperature profile on particle size, morphology, and surface element distribution. Distinct morphologies are observed with different precursor compositions, ranging from smooth spherical lactose microparticles to the buckled shape for composites containing silica nanoparticles. The formation of such morphology is qualitatively interpreted by using Peclet number, indicating that the presence of the suspended silica nanoparticles facilitates shell formation at the early stage of the drying process. As the drying continue, such shell is subject to buckling, induced by the capillary force due to the lower mechanical integrity inside the droplet. Post calcination, transmission electron micrographs of Eu(III)/silica nanoparticles/lactose microcomposites confirm the formation of nano-sized Eu 2 O 3 homogeneously embedded on the silica shell. Photoluminescence spectra of these particles indicate that enhancement of photoluminescence intensity is directly related to the europium loading, which could be adjusted from the precursor composition. This work demonstrates a scalable route to assemble relatively complex composites with uniform properties, without extensive conjugation or purification steps commonly required in wet chemistry-based processes.

On enhancing the solubility of curcumin by microencapsulation in whey protein isolate via spray drying

“…WPI solutions at the concentration of 5 wt% with saturated amounts of curcumin (59.5 ± 2.7 mg/mL) were spray dried by a microfluidic jet spray dryer (Wu et al, 2011a). Monodisperse droplets were generated from the precursor solution by a microfluidic aerosol nozzle system, with an orifice diameter of 75 mm.…”

Formation process of core‐shell microparticles by solute migration during drying of homogenous composite droplets

“…31 The subsequent events would depend on the properties of the solids. 4,32,33 Solids with high mobility or high solubility in water could continue to equilibrate with the receding water interface, and thus the droplet keeps shrinking without apparent shell formation, as in the drying of pure silica droplets (Fig. 4b).…”

Three-Dimensional Numerical Investigation of a Mono-Disperse Droplet Spray Dryer: Validation Aspects and Multi-Physics Exploration

“…A nozzle technology was further developed and evaluated by Wu et al [3,4]. Using this technology, it has been more definitive to study the product characteristics and to investigate how these characteristics were formed under the influences of different inlet temperatures, velocities, feed solution concentrations and so on.…”