Biomedical subjects

Adam J Rondinone

Publications and source records attributed to Adam J Rondinone.

3 recordsLinked to original sources

PubMed2006

Metastable tetragonal phase CdWO4 nanoparticles synthesized with a solvothermal method.

CdWO4 has only previously been reported in the monoclinic, or wolframite, phase. Here we report the first metastable, tetragonal or scheelite, CdWO4 nanopowder. The tetragonal CdWO4 was synthesized by a propylene glycol solvothermal method. The scheelite phase is stabilized by a combination of high surface area and surface complexation by the propylene glycol. The CdWO4 is stable at 1 bar to 300 degrees C, and converts back to the monoclinic wolframite phase between 300 and 500 degrees C. The nanopowder exhibits cubic morphology and the average particle size of the nanopowder is around 50 nm.

Journal Article↗

PubMed2006

Self-assembled colloidal crystals from ZrO2 nanoparticles.

Ordered three-dimensional (3-D) assemblies of nanocrystalline zirconia were synthesized from aqueous suspensions of ZrO(2) nanoparticles without the need for hydrocarbon surfactants or solvents to control colloidal crystal growth. Nanoparticles were suspended in mild acid and subsequently titrated from low to neutral pH. The solubility was reduced as the surfaces were neutralized, promoting assembly of the nanoparticles into ordered monoliths. TEM measurements indicated the formation of three-dimensional, hexagonal faceted, micrometer-sized colloidal crystals composed of 4 nm diameter ZrO(2) nanoparticles. Lacking organic surfactants, the colloidal crystals were exceptionally robust and were sintered at high temperatures (300-500 degrees C) for further stability. Small-angle X-ray scattering (SAXS) measurements demonstrate that the samples become progressively more amorphous above 350 degrees C, although some ordered domains of nanoparticles persist. Additionally, the heat treatment dramatically increases the surface area of the colloidal crystals as water and residual organics are desorbed, revealing highly controlled interstitial spaces and pores.

Journal Article↗

PubMed2005

Facile, alternative synthesis of lanthanum phosphate nanocrystals by ultrasonication.

Highly luminescent, rhabdophane (Ce(0.33)La(0.66))PO4.nH2O nanorods and nanoparticles were prepared in aqueous solutions by ultrasonication, at pH 1 and pH 12, respectively. Both nanorods (5 to 9 nm wide and several tens to several hundreds nm long) and nanoparticles (elongated, connected 5 nm particles) were as small and as uniform as products obtained from methods that utilize complexing agents or surfactants, only with no complexing agent. This method of synthesis by ultrasonication is a fast and simple method and it is expected to be applicable for the synthesis of other nanocrystalline lanthanide phosphates.

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