Search

To study the development, characterisation, and drug release of one‐ and two‐layered thin films based on organic polymers [poly(D,L‐lactide‐co ‐glycolide) lactide:glycolide (65:35), poly(D,L‐lactide‐co ‐glycolide) lactide:glycolide (75:25), and polycaprolactone] and dexamethasone. To examine their applicability for intraocular lenses (IOLs) and function in intraocular drug delivery systems. Four series of thin films, single and double‐layer, were prepared by the spin‐coating method on a silicon substrate. The films were studied using atomic force microscopy and spectroscopic ellipsometry. The release rate of dexamethasone was studied for a period of ten weeks. Series A and C demonstrated the formation of large dexamethasone aggregates. The monolayer films of series C and D formed pores, in agreement with previous findings. The spectroscopic ellipsometry study demonstrated that the samples were transparent. The drug release study demonstrated that dexamethasone was released during the first 6 weeks at a desirable rate. The films exhibited properties suitable for use in intraocular drug delivery systems. The single‐layer thin films demonstrated a sufficient encapsulation of dexamethasone and appropriate release of the therapeutic substance. Further studies are necessary to investigate the possibility of developing the films directly on the surface of the IOL. [ABSTRACT FROM AUTHOR]

Abstract: Ultrathin polymeric films consisting of poly(9,9‐di‐n‐octylfluorenyl‐2,7‐diyl) (F8) blended with poly(9,9‐dioctylfluorene‐alt‐benzothiadiazole) (F8BT) grown onto PEDOT:PSS/ITO/PET were investigated by X‐ray photoelectron spectroscopy (XPS), depth‐profiling XPS, reflection electron energy loss spectroscopy (REELS) and angle‐dependent X‐ray absorption spectroscopy (XAS) to gain information on the films' electronic, order and interface properties. AFM studies provide valuable information on the films' nanotopographical properties and homogeneity. Spectroscopic ellipsometry and photoluminescence spectroscopy were used also to obtain information on the optoelectronic properties. Well‐ordered films were observed from the XAS analysis, measured at the sulfur K absorption edge. XPS measurements demonstrated that the surface composition of the polymer thin films prepared by a spin‐coating wet‐chemical deposition method matches the expected F8:F8BT blend stoichiometry. The interfacial properties were studied through an argon ion sputtering process coupled to the XPS acquisition, showing an enhancement of oxygen components at the interface. The films' inhomogeneity was verified by AFM images and analysis. We obtained a value of 3.1 eV as the electronic bandgap of the F8:F8BT film from REELS data, whereas analysis of the spectroscopic ellipsometry spectra revealed that the optical bandgap of F8:F8BT has a value of 2.4 eV. A strong green emission was obtained for the produced films, which is in agreement with the expected emission due to the 1:19 ratio of the F8 and F8BT blended polymers. © 2018 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

White Organic Light‐Emitting Diodes (WOLEDs) have attracted an enormous interest because they can be implemented in numerous lighting applications as next‐generation light sources. Several device setups such as multilayer, blends, or single layers of polymer nanomaterials have been proposed to achieve white light emission. In this work, novel copolymers bearing blue, yellow, and red chromophores, are used for the fabrication of WOLED systems including single emissive layer. These terpolymers provide easy tuning of white color emission by selecting the appropriate ratios between the chromophores while being solution processable from typical organic solvents, like chlorobenzene (CB), o‐dichlorobenzene (o‐DCB), etc. The chromophores can be directly excited by capturing charge carriers or through energy transfer from the other chromophores. Incomplete energy transfer between the chromophores is necessary to get white light as combined emission from all of them. The opto‐electronic and electro‐optical characterization is carried out by NIR–Vis–far UV spectroscopic ellipsometry, photoluminescence, and electroluminescence, to provide valuable information toward the optimization and functionalization of these WOLED devices. Novel copolymers bearing blue, yellow, and red chromophores, are used for the fabrication of white organic light‐emitting diode (WOLED) systems including single emissive layer. These terpolymers provide easy tuning of white colour emission by selecting the appropriate ratios between the chromophores while being solution processable. The opto‐electronic and electro‐optical characterization is carried out by NIR–Vis–far UV spectroscopic ellipsometry, photoluminescence, and electroluminescence. [ABSTRACT FROM AUTHOR]