Вплив вуглецевих нанотрубок на формування нанокомпозитів на основі термостійких сітчастих поліціануратів

Досліджено вплив мультистінних вуглецевих нанотрубок (МСВНТ) на формування нанокомпозитів на основі термостійких сітчастих поліціануратів, отриманих in situ поліциклотримеризацією олігомерів диціанового естеру бісфенолу А (ДЦБА) за присутності різного вмісту МСВНТ, та морфологію синтезованих нанокомпозитів, їх структуру і фізико-хімічні властивості. Встановлено, що за невеликого вмісту МСВНТ (0.03—0.06 % мас.) синтезовані нанокомпозити мають високі показники модулю пружності, зафіксовано суттєве підвищення величин межі міцності sр (на 62—94 % у залежності від вмісту МСВНТ), зроблено висновок про взаємодію нанонаповнювача з полімерною матрицею на нанорівні.Исследовано влияние мультистенных углеродных нанотрубок (МСУНТ) на формированние нанокомпозитов на основе термостойких сеточных полициануратов, полученных in situ полициклотримеризацией олигомеров дицианового эстера бисфенола А (ДЦБА) в присутствии различного количества МСУНТ, и морфологию синтезированных нанокомпозитов, их структуру и физико-химические свойства. Установлено, что при небольшом содержании МСУНТ (0.03—0.06 % мас.) синтезированные нанокомпозиты имеют высокие показатели модуля упругости, зафиксировано значительное повышение величины границы прочности sр (на 62—94 % в зависимости от содержания МСУНТ), сделан вывод о взаимодействии нанонаполнителя с полимерной матрицей на наноуровне.An influence of multiwall carbon nanotubes (MWCNT) on formation of nanocomposites based on thermostable polycyanurate networks obtained by in situ polycyclotrimerization of oligomers of dicyanate ester of bisphenol A (DCBA) in the presence of different amount of MWCNT and on their morphology, structure and physical-chemical properties has been studied. It has been found that at low MWCNT content (0.03—0.06 % wt.) the nanocomposites synthesized have high elastic modulus, significant increasing value of strength at break (by 62—94 % depending on MWCNT content) has been observed, the nanoscale interaction of the nanofiller with polymer matrix is discussed

Self-Aligned Bilayers for Flexible Free-Standing Organic Field-Effect Transistors

[Image: see text] Free-standing and flexible field-effect transistors based on 6,13-bis(triisopropylsilylethynyl)-pentacene (TIPS-pentacene)/polystyrene bilayers are obtained by well-controlled phase separation of both components. The phase separation is induced by solvent vapor annealing of initially amorphous blend films, leading to crystallization of TIPS-pentacene as the top layer. The crystallinity and blend morphology strongly depend on the molecular weight of polystyrene, and under optimized conditions, distinct phase separation with a well-defined and trap-free interface between both fractions is achieved. Due to the distinct bilayer morphology, the resulting flexible field-effect transistors reveal similar charge carrier mobilities as rigid devices and additionally pronounced environmental and bias stress stabilities. The performance of the flexible transistors remains stable up to a strain of 1.8%, while above this deformation, a close relation between current and strain is observed that is required for applications in strain sensors

Minimalism in Radiation Synthesis of Biomedical Functional Nanogels

A scalable, single-step, synthetic approach for the manufacture of biocompatible, functionalized micro- and nanogels is presented. In particular, poly(N-vinyl pyrrolidone)-grafted-(aminopropyl)methacrylamide microgels and nanogels were generated through e-beam irradiation of PVP aqueous solutions in the presence of a primary amino-group-carrying monomer. Particles with different hydrodynamic diameters and surface charge densities were obtained at the variance of the irradiation conditions. Chemical structure was investigated by different spectroscopic techniques. Fluorescent variants were generated through fluorescein isothiocyanate attachment to the primary amino groups grafted to PVP, to both quantify the available functional groups for bioconjugation and follow nanogels localization in cell cultures. Finally, a model protein, bovine serum albumin, was conjugated to the nanogels to demonstrate the attachment of biologically relevant molecules for targeting purposes in drug delivery. The described approach provides a novel strategy to fabricate biohybrid nanogels with a very promising potential in nanomedicine

Role of geometry, substrate and atmosphere on performance of OFETs based on TTF derivatives

Abstract We report a comparative study of OFET devices based on zone-cast layers of three tetrathiafulvalene (TTF) derivatives in three configurations of electrodes in order to determine the best performing geometry. The first testing experiments were performed using SiO 2 /Si substrates. Then the optimum geometry was employed for the preparation of flexible OFETs using Parylene C as both substrate and dielectric layer yielding, in the best case, to devices with μ FET = 0.1 cm 2 /Vs. With the performed bending tests we determined the limit of curvature radius for which the performance of the OFETs is not deteriorated irreversibly. The investigated OFETs are sensitive to ambient atmosphere, showing reversible increase of the source to drain current upon exposition to air, what can be explained as doping of TTF derivative by oxygen or moisture

A review on radiation-induced nucleation and growth of colloidal metallic nanoparticles

This review presents an introduction to the synthesis of metallic nanoparticles by radiation-induced method, especially gamma irradiation. This method offers some benefits over the conventional methods because it provides fully reduced and highly pure nanoparticles free from by-products or chemical reducing agents, and is capable of controlling the particle size and structure. The nucleation and growth mechanism of metallic nanoparticles are also discussed. The competition between nucleation and growth process in the formation of nanoparticles can determine the size of nanoparticles which is influenced by certain parameters such as the choice of solvents and stabilizer, the precursor to stabilizer ratio, pH during synthesis, and absorbed dose

Dexamethasone intravitreal implant in previously treated patients with diabetic macular edema : Subgroup analysis of the MEAD study

Background: Dexamethasone intravitreal implant 0.7 mg (DEX 0.7) was approved for treatment of diabetic macular edema (DME) after demonstration of its efficacy and safety in the MEAD registration trials. We performed subgroup analysis of MEAD study results to evaluate the efficacy and safety of DEX 0.7 treatment in patients with previously treated DME. Methods: Three-year, randomized, sham-controlled phase 3 study in patients with DME, best-corrected visual acuity (BCVA) of 34.68 Early Treatment Diabetic Retinopathy Study letters (20/200.20/50 Snellen equivalent), and central retinal thickness (CRT) 65300 \u3bcm measured by time-domain optical coherence tomography. Patients were randomized to 1 of 2 doses of DEX (0.7 mg or 0.35 mg), or to sham procedure, with retreatment no more than every 6 months. The primary endpoint was 6515-letter gain in BCVA at study end. Average change in BCVA and CRT from baseline during the study (area-under-the-curve approach) and adverse events were also evaluated. The present subgroup analysis evaluated outcomes in patients randomized to DEX 0.7 (marketed dose) or sham based on prior treatment for DME at study entry. Results: Baseline characteristics of previously treated DEX 0.7 (n = 247) and sham (n=261) patients were similar. In the previously treated subgroup, mean number of treatments over 3 years was 4.1 for DEX 0.7 and 3.2 for sham, 21.5 % of DEX 0.7 patients versus 11.1 % of sham had 6515-letter BCVA gain from baseline at study end (P = 0.002), mean average BCVA change from baseline was +3.2 letters with DEX 0.7 versus +1.5 letters with sham (P = 0.024), and mean average CRT change from baseline was -126.1 \u3bcm with DEX 0.7 versus -39.0 \u3bcm with sham(P < 0.001). Cataract-related adverse events were reported in 70.3 % of baseline phakic patients in the previously treated DEX 0.7 subgroup; vision gains were restored following cataract surgery. Conclusions: DEX 0.7 significantly improved visual and anatomic outcomes in patients with DME previously treated with laser, intravitreal anti-vascular endothelial growth factor, intravitreal triamcinolone acetonide, or a combination of these therapies. The safety profile of DEX 0.7 in previously treated patients was similar to its safety profile in the total study population