The colloidal stability of miniemulsions in the presence of RAFT or other control agents for controlled free radical polymerization is examined. A derivation, based on Lifshitz-Slyozov-Wagner (LSW) theory, is proposed here to evaluate the effect of a RAFT agent on the diffusional stability of the miniemulsions before the onset of polymerization. Results indicate that, depending on the hydrophobicity of the control agent, its presence may augment or detract from the effectiveness of the costabilizer in preventing diffusional instability due to Ostwald ripening.
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http://dx.doi.org/10.1021/la060762t | DOI Listing |
Chem Asian J
December 2024
State Key Laboratory for Advanced Metals and Materials, School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing, 100083, P. R. China.
Gold nanoclusters (AuNCs), which are approximately 2 nm in size, exhibit distinctive photophysical and catalytic properties, but their performance is often compromised by environmental factors. To mitigate these challenges, attempts have been made to incorporate AuNCs into polymer matrices to enhance their stability. Miniemulsion polymerization has proven to be an effective method for fabricating organic-inorganic composites.
View Article and Find Full Text PDFJ Am Chem Soc
October 2024
Department of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
Conjugated polymer nanoparticles (CPNs) can be synthesized by a Suzuki-Miyaura cross-coupling miniemulsion polymerization to give stable dispersions with a high concentration of uniform nanoparticles. However, large amounts of added surfactants are required to stabilize the miniemulsion and prevent the aggregation of the nanoparticles. Removal of the excess surfactant is challenging, and residual surfactant in thin films deposited from these dispersions can reduce the performance of optoelectronic devices.
View Article and Find Full Text PDFJ Pharm Sci
August 2024
Harvard Medical School, Boston, MA, USA.
The physical stability of parenteral dispersions for delivery of drugs to patients is of particular clinical importance, given their general overall superior bioavailability compared to other routes of administration. Although official pharmacopeial methods for lipid injectable emulsions have been established for triglyceride oil-in-water dispersions (i.e.
View Article and Find Full Text PDFNanoscale Adv
December 2023
Institute of Macromolecular Chemistry, Czech Academy of Sciences Heyrovského nám. 2 162 00 Prague 6 Czech Republic
In this report, upconverting NaYF:Yb,Er nanoparticles (UCNPs) were synthesized by high-temperature coprecipitation of lanthanide chlorides and encapsulated in poly(glycerol monomethacrylate) (PGMMA). The UCNP surface was first treated with hydrophobic penta(propylene glycol) methacrylate phosphate (SIPO) to improve colloidal stability and enable encapsulation by reversible addition-fragmentation chain transfer miniemulsion polymerization (RAFT) of glycidyl methacrylate (GMA) in water, followed by its hydrolysis. The resulting UCNP-containing PGMMA particles (UCNP@PGMMA), hundreds of nanometers in diameter, were thoroughly characterized by transmission (TEM) and scanning electron microscopy (SEM), dynamic light scattering (DLS), infrared (FTIR) and fluorescence emission spectroscopy, and thermogravimetric analysis (TGA) in terms of particle morphology, size, polydispersity, luminescence, and composition.
View Article and Find Full Text PDFNanoscale
December 2023
Department of Material Innovation, Graduate School of Pure and Applied Science, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8573, Japan.
Thermally tolerant polymer optical resonators are fabricated from a stereocomplex of poly(L-lactic acid) and poly(D-lactic acid) through the oil-in-water miniemulsion method. The thermal stability of the microspheres of the stereocomplex poly(lactic acid) (SC-PLA) is superior to that of the homochiral poly(lactic acid) (HC-PLA). As a result of the high thermal stability, the optical resonator properties of the SC-PLA microspheres are preserved at an elevated temperature of up to 230 °C, which is 70 °C higher than that of microspheres formed from HC-PLA.
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