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"البوليمرات تجارب"
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Optical Studies of Conjugated Polymer Nanparticles Prepared by Various Emulsion Polymerisation Methods
The Susuki-Miyaura cross coupling polymerisation approach to formation of emissive conjugated polymer nanoparticles was presented and the flexibility of the method for preparation of particles with different emission colours was demonstrated. The as-prepared nanoparticle dispersions were clear (not turbid) and the particle hydrodynamic diameters were small, < 60 nm. Zeta potentials of the particles were strongly negative, consistent with the presence of negative surface charge on the particles, possibly due to defect formation. Spectroscopic data revealed that the particle absorption/emission was characteristic of the parent polymer. Values of photoluminescence quantum yields and lifetimes of particle dispersions were determined. The estimated radiative decay rate constants were similar to those of fluorescence dyes (ca. 108 s-1) used in flow cytometry or fluorescence imaging, and higher than those of quantum dots. Photo stability studies carried out for aqueous nanoparticle dispersions indicated that some particle types exhibited mild photo brightening under continuous illumination with stability generally observed for all particles. These observations demonstrated that the particles were more stable than conventional molecular fluorophores. Single nanoparticle imaging studies confirmed that the particles were bright with good signal-to-background characteristics being observed for all particle types. Measurements of single particle photo bleaching trajectories indicated that the majority of particles exhibited largely continuous photo bleaching behavior consistent with the multichromophoric character expected for particles composed of aggregated conjugated polymer chains with comparatively large total numbers of emissive chromophores. A few particles exhibited fluorescence intermittency or emission blinking behavior during photo bleaching which was ascribed to reversible, time-varying fluctuations in the fraction of chromophores in the emitting ('on\") state present within particles composed of relatively small total numbers of emissive chromophores. Single particle death numbers of ca.
Journal Article
Polymers for Medical Applications
Polymers are compounds with large size have several applications in many areas, and most important of these applications in the field of medicine, where some polymers enter in the formation of active substances in the drug and some is used as a carrier for these active substances and each used in the manufacture of artificial organs, due to their properties which differ than non-polymeric substance In this research we'll show some of the uses of polymers in medicine CONTENTS: 1) Introduction to polymers: a) Meaning. b) Classification. c) Synthesis. d) Applications. 2) Application of Polymers in Dosage Forms: a) Convention: - Disperse Systems. - Solid dosage forms. - Tran-sdermal drug delivery systems. b) Drug release: - Immediate-Release Dosage Forms. - Modified-Release Dosage Forms. - Stimuli Responsive Drug Release. c) Ocular dosage: - Liquid dosage. - Semi solid dosage. 3) Application of Polymers in Artificial Organs: a) Prosthesis: - Artificial Joints. - Artificial Skin. - Polymeric blood substitutes. b) Cardiovascular application: - Artificial Heart Valves. - Artificial Heart pumps. c) Therapeutic devices: - Hemodialysis. - Oxygen transport membrane. d) Dental application. 4) Another Medical Applications: a) Bio absorbable Polymers for surgical applications. b) Adhesives for medical applications. 5) Application of Polymers in Packaging.
Conference Proceeding
Coulomb Blockade Behavior in PVA/PEG/Ag Nanocomposite
Poly (vinyl alcohol)/poly (ethylene glycol)/silver nanoparticles (PVA/PEG/ Ag nanoparticles) thin films with different concentrations of silver nanoparticles were prepared using casting technique. properties of samples have been investigated using electrical properties. Increases the electrical conductivity and Coulomb blockade occur by maximum Ag nano particles concentrations in the samples.
Journal Article