A versatile approach for the preparation of thermosensitive PNIPAM core-shell microgels with nanoparticle cores.
Explore the source record for details and available documents.
Journal Article↗
Biomedical subjects
Isabel Pastoriza-Santos
Publications and source records attributed to Isabel Pastoriza-Santos.
Bending contours in silver nanoprisms.
A detailed electron microscopy analysis is reported on the structure of silver nanoprisms synthesized by controlled photoinduced aggregation of Ag nanoparticles. Bending of the nanoprism (111) face is directly revealed in the presence of fringes in both bright and dark field TEM images, which are unequivocally assigned to bending contours. Such contours can be individually imaged through shifting of the objective aperture and selectively allowing transmission of the corresponding diffraction spot. The assignment of a bent structure is supported by images of the lateral sides of the prisms, and high-resolution images where apparent changes in the lattice constant are observed.
Journal Article↗
Optically active poly(dimethylsiloxane) elastomer films through doping with gold nanoparticles.
Poly(dimethylsiloxane) (PDMS) elastomer films synthesized through a cross-linking reaction between hydroxyl-terminated or vinyl-terminated PDMS have been homogeneously doped with silica-coated Au nanoparticles. The nanocomposite synthesis involves mixing a preformed colloid of surface-modified metal nanoparticles with the elastomer film precursors. The homogeneous distribution of nanoparticles is demonstrated through the presence of well defined plasmon absorbance bands in the visible, which clearly show that the composites retain the characteristic optical properties of single Au nanoparticles. The metal particle concentration could be easily tailored either through the amount or the concentration of the nanoparticle colloid added. Since the Au nanoparticles are not cross-linked to the polymer and the concentration of particles is relatively low, we postulate that the presence of the nanoparticles does not affect the mechanical properties of the films, though this remains to be confirmed.
Dimethylpolysiloxanes↗
On the temperature stability of gold nanorods: comparison between thermal and ultrafast laser-induced heating.
The response of gold nanorods to both thermal and ultrafast laser-induced heating has been examined. The thermal heating experiments show structural changes that occur on timescales ranging from hours to days. At the highest temperature examined (250 degrees C) the nanorods are transformed into spheres within an hour. On the other hand, no structural changes are observed in the laser-induced heating experiments up to temperatures of 700 +/- 50 degrees C. This is attributed to thermal diffusion in the laser experiments. Measurements of the period of the extensional mode of the nanorods using time-resolved spectroscopy show a significant softening at high pump laser powers. However, the decrease in the period is less than expected from bulk Young's modulus vs. temperature data.
Journal Article↗
Tunable whispering gallery mode emission from quantum-dot-doped microspheres.
We describe the synthesis of quantum-dot (QD) doped silica microspheres and a method by which it is possible to fine-tune the position of the whispering gallery modes (WGMs) produced by the fluorescence emission of CdSe@ZnS doped silica microspheres (5.06 mum in diameter). The method is based on small perturbations to the sphere's refractive index caused by adsorption of thin layers of polyelectrolytes and modification of the radial position of the nanocrystals within the microsphere by means of deposited silica shells.
Adsorption↗
Flexible ureasil hybrids with tailored optical properties through doping with metal nanoparticles.
Hybrid organic-inorganic nanocomposites containing uniform distributions of metal nanoparticles have been prepared by mixing a preformed nanoparticle colloid with the precursors of a ureasil, prior to the sol-gel transition. These nanocomposites possess not only high optical quality and optical features dictated by the size and shape of the nanoparticle dopants but also a high degree of flexibility, which can largely enhance the range of applications in practical devices. The deposition of a uniform silica shell on the nanoparticle surface prior to the sol-gel transition was found to be required to maintain the colloidal stability during the process and, thus, to retain the optical properties in the final nanocomposite material. This method can be readily extended to other materials, such as semiconductor and magnetic nanoparticles.
Journal Article↗