Microparticle synthesis

Fig. 10 Droplet microfluidics for microparticle synthesis, (a) Janus particle synthesis by coflowing two monomer streams. Reproduced with permission from [82]. (b) Channel geometry facilitated aspherical particles synthesis. Reproduced with permission from [111], (c) Multiple emulsion templated composite particles synthesis. Reproduced with permission from [112]...

D. Dendukuri, D. Pregibon, J. Collins, T. Hatton, and P. Doyle, Continuous-flow lithography for high-throughput microparticle synthesis, Nature Materials, 5, 365-369, 2006. 

Spegel, P., L. Schweitz, et al. (2001). Molecularly imprinted microparticles for capillary electrochromatography studies on microparticle synthesis and electrolyte composition. Electrophoresis 22(17) 3833-3841. 

Microfluidic synthesis Microparticle synthesis Nanoparticle synthesis Particle synthesis... 

B. H. Robinson, A. N. Khan-Lodhi and T. Towey, Microparticle synthesis and characterization in... 

Won CW et al (2009) Porous silicon microparticles synthesis by solid flame technique. Microporous Mesoporous Mater 126 166-170... 

Dendukuri D, Pregibon DC, ColUns J, Hatton TA, Doyle PS (2006) Continuous-flow Uthc raphy for high-throuput microparticle synthesis. Nat Mater 5 365-369... 

Picoliter-Sized Reactors for Mesoporous Microparticle Synthesis... 

Fig. 9. Schematic representation of a catalyst for ethylene oxide synthesis (not to scale). The porous support particle consists of microparticles held together...

The pore size and distribution in the porous particles play essential roles in NPS synthesis. For example, only hollow capsules are obtained when MS spheres with only small mesopores (<3 nm) are used as the templates [69]. This suggests that the PE has difficulty infiltrating mesopores in this size range, and is primarily restricted to the surface of the spheres. The density and homogeneity of the pores in the sacrificial particles is also important to prepare intact NPSs. In a separate study, employing CaC03 microparticles with radial channel-like pore structures (surface area 8.8 m2 g 1) as sacrificial templates resulted in PE microcapsules that collapse when dried, which is in stark contrast to the free-standing NPSs described above [64]. 

Figure 2.12 Nanoparticle synthesis flow-chart (top) and schematic of the combined microemulsion/sol-gel process to produce doped silica microparticles. (Reproduced from ref. 7, with permission.)...

Following route A (Fig. 1), Yan Xiao et al. reported the chemoenzymatic synthesis of poly(8-caprolactone) (PCL) and chiral poly(4-methyl-8-caprolactone) (PMCL) microparticles [5]. The telechelic polymer diol precursors were obtained by enzymatic polymerization of the corresponding monomers in the presence of hexanediol. Enzymatic kinetic resolution polymerization directly yielded the (R)-and (S )-enriched chiral polymers. After acrylation using acryloylchloride, the chiral and nonchiral particles were obtained by crosslinking in an oil-in-water emulsion photopolymerization. Preliminary degradation experiments showed that the stereoselectivity of CALB is retained in the degradation of the chiral microparticles (Fig. 2). 

Fig. 2 Synthesis of acrylated chiral PMCL left) and microparticles (right) obtained from acry-lated polymers by oil-in-water emulsion photopolymerization [5]...

Silva et al. (2006) studied starch-based microparticles as a novel strategy for tissue engineering applications. They developed starch-based microparticles, and evaluated them for bioactivity, cytotoxicity, ability to serve as substrates for cell adhesion, as well as their potential to be used as delivery systems either for anti-inflammatory agents or growth factors. Two starch-based materials were used for the development of starch-based particulate systems (1) a blend of starch and polylactic acid (SPLA) (50 50 w/w) and (2) a chemically modifled potato starch, Paselli II (Pa). Both materials enabled the synthesis of particulate systems, both polymer and composite (with BG 45S5). A simple solvent extraction method was employed for the synthesis of SPLA and SPLA/BG microparticles, while for Pa and Pa/BG... 

Silva, G. A., Costa, F. J., Coutinho, O. P, Radin, S., Ducheyne, R, Reis, R. L. (2004). Synthesis and evaluation of novel bioactive composite starch/bioactive glass microparticles. J. Biomed. Mater. Res. Part A., 70A 3), 442 49. 

However, in recent years it has been shown that single crystals and dispersed materials are not so different as to hinder fruitful comparisons of results from the separate fields (22,23). It has been shown that when proper synthesis and sintering procedures are adopted, oxide and chloride microparticles are obtained that can assume the crystalline habits of very well-defined polyhedra and consequently can expose facelets with regularity not significantly different from that of single crystals (22, 23). 

The use ofthese materials as beds for microparticles ofmetals has been successful. A more ambitious idea would be to use the structure of the polymer surface itself and the skills of the organic synthesis chemist to supply groups with specific structures, i.e., to design catalysts (see Section 11.6.3). 

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