Preparation of polymer@titania raspberry-like core–corona composite via heterocoagulated self-assembly based on hydrogen-bonding interaction

Microparticles of Sericin-Dextran Conjugate for Improving the Solubility of Antiviral Drug

A novel sericin-dextran conjugate (SDC) and self-assembled microparticles has been prepared for improving solubility of atazanavir. Microparticles of SDC were assembled by the reprecipitation method. The size and morphology of SDC microparticles could be adjusted by the concentration and solvents. Low concentration was conducive to the preparation of microspheres. Heterogeneous microspheres could be prepared in ethanol with the range of 85-390 nm, and hollow mesoporous microspheres in propanol with an average particle size of 2.5-22 µm. The aqueous solubility of atazanavir was improved to 2.22 mg/mL in buffer solutions at pH 2.0 and 1.65 mg/mL at pH 7.4 by SDC microspheres. In vitro release of atazanavir from hollow microspheres of SDC exhibited a slower release, had the lowest linear cumulative release in basic buffer (pH 8.0), and the most rapid double exponential diphase kinetic cumulative release in acid buffer (pH 2.0).

What is the role of PEO chains in the assembly of core-corona supraparticles in aqueous dispersions?

Hypothesis The assembly of core-corona supraparticles in aqueous dispersions has been regularly assisted by auxiliary monomers/oligomers which modify the individual particles with, e.g., surface grafting of polyethylene oxide (PEO) chains or other hydrophilic monomers. However, this modification complicates the preparation and purification procedures and increases potential upscaling efforts. Hybrid polymer-silica core-corona supracolloids could be more simply assembled if the PEO chains from surfactants, typically used by default as polymer stabilizers, concomitantly act as assembly promotors. The supracolloids assembly could therefore be more easily achieved without requiring particles functionalization or post-purification steps. Methods The self-assembly of supracolloidal particles prepared with PEO-surfactant stabilized (Triton X-405) and/or PEO-grafted polymer particles is compared to differentiate the roles of the PEO chains in the assembly of core-corona supraparticles. Using time-resolved dynamic light scattering (DLS) and cryogenic transmission electron microscopy(cryo-TEM), the effect of concentration of PEO chains (from surfactant) on the kinetics and dynamics of supracolloids assembly is investigated. Self-consistent field (SCF) lattice theory was used to numerically study the distribution of PEO chains at the interfaces present in the supracolloidal dispersions. Findings The PEO based surfactant can be used as assembly promoter of core-corona hybrid supracolloids due to its amphiphilic nature and via establishing hydrophobic interactions. The concentration of the PEO surfactant, and especially the PEO chains distribution over the different interfaces, crucially affect the supracolloids assembly. A simplified pathway for preparing hybrid supracolloidal particles with a well-controlled corona coverage over polymer cores is presented.

Synthetic strategies for raspberry-like polymer composite particles

The strategies used for the preparation of raspberry-like polymer composite particles are summarized comprehensively.

Self-assembly of strawberry-like organic–inorganic hybrid particle clusters with directionally distributed bimetal and facile transformation of the core and corona

Controllable structure of organic–inorganic hybrid particle clusters were successfully fabricated by self-assembly which derived from the strong interaction between carboxyl groups of the organic particles and amino groups of the inorganic particles.

A facile strategy to fabricate covalently linked raspberry-like nanocomposites with pH and thermo tunable structures

A simple and controllable route to prepare covalently bonded raspberry-like composite particles with pH and thermal dual-responsiveness.

Robust hybrid raspberry-like hollow particles with complex structures: a facile method of swelling polymerization towards composite spheres

A novel robust hybrid raspberry-like TiO2/PS hollow particles with complex double-shelled structures have been fabricated in large quantities by a facile swelling polymerization approach based on commercially available hollow polystyrene (PS) spheres. The crosslinked-PS protrusions are wedged firmly into the TiO2 shell, making the resultant particles both chemically and mechanically robust. By simply tuning the monomer concentration, the hierarchical morphology (the size and number of protrusion) of the surfaces can be well-controlled. Due to the dual-sized hierarchical morphology, the particulate coating possesses superhydrophobicity (water contact angle ≈ 161°). Moreover, the well-compartmentalized character is similar to that of typical Janus particles. The special particles with interfacial activity can stabilize water-in-toluene (w/o) emulsions well. Meanwhile, a TiO2 double-shelled hollow sphere with a complex structure is achieved by calcination or solvent treatment. All these unique features derived from a readily available method will endow the products with a broader range of applications.

CdS nanoparticles anchored on the surface of yeast via a hydrothermal processes for environmental applications

CdS@yeast hybrid microspheres synthesized via hydrothermal method were applied for removal of methylene blue (MB).

Synthesis of raspberry-like poly(styrene-glycidyl methacrylate) particles via a one-step soap-free emulsion polymerization process accompanied by phase separation

We herein report a facile method to prepare raspberry-like poly(styrene-glycidyl methacrylate) [P(S-GMA)] particles with controllable structure via a one-step soap-free emulsion polymerization process accompanied by phase separation. In this method, corona particles with a size of 10-20 nm were produced in situ in the later polymerization stage by the migrating of S-enriched polymers from GMA-enriched core particles. The size of the corona particles and the roughness of the raspberry-like particles can be easily controlled by adjusting the amount of styrene (S), glycidyl methacrylate (GMA), and divinylbenzene (DVB). The structure of raspberry-like P(S-GMA) particles was confirmed by transmission electron microscopy, scanning electron microscopy, and atomic force microscopy. A possible mechanism of the formation of raspberry-like particles was proposed.