Encontrados 5 documentos, a visualizar página 1 de 1
High nonlinear optical anisotropy of urea nanofibers
Isakov, D. V.; Gomes, E. de Matos; Belsley, M.; Almeida, B. G.; Martins, Albino; Neves, N. M.; Reis, R. L.Nanofibers consisting of the optically nonlinear organic molecule urea embedded in both poly(ethylene oxide) (PEO) and poly(vinyl alcohol) (PVA) polymers were produced by the electrospinning technique. The second-harmonic generation produced by aligned fiber mats of these materials displays a strong dependence on the polarization of the incident light. In PVA-urea nanofibers the effectiveness in generating of t...
Synthesis of polymer-based triglycine sulfate nanofibres by electrospinning
Isakov, D. V.; Martins, Albino; Gomes, E. de Matos; Bdikin, Igor; Guimarães, Ana; Dekola, Tatjana; Almeida, B. G.; Neves, N. M.; Reis, R. L.In this work we present the synthesis and characterization of polyethylene oxide (PEO) based triglycine sulfate (NH2(CH2OOH)3H2S04, TGS) nanofibres obtained by electrospinning. The fibres, with typical diameters of about 190–750 nm and above several hundred micrometres in length, present the nanocrystals of TGS embedded in a polymer matrix. The obtained nanofibres were characterized by FT-IR spectroscopy and th...
Unusual supramolecular assembly and nonlinear optical properties of l-histidini...
Gomes, E. de Matos; Rodrigues, V. H.; Costa, M. M. R.; Belsley, M. S.; Cardoso, P. J. M.; Gonçalves, C. F.; Proença, F.A new nonlinear optical material, l-histidinium hydrogen malate, has been synthesized. The crystal structure was determined at 90 K by single-crystal X-ray diffraction in order to analyze its supramolecular structure. A new building block type has been found. The malate anions form head-to-side infinite chains parallel to [100], via O-H...O interactions, instead of the usual head-to-tail infinite chains found i...
Antiferroelectric ADP doping in ferroelectric TGS crystals
Arunmozhi, G.; Lanceros-Méndez, S.; Gomes, E. de MatosCrystal growth, morphology, hysteresis and dielectric measurements on 20 mol% ammonium dihydrogen phosphate (ADP)doped triglycine sulphate (TGS) crystals are reported. Crystals grew with morphology similar to phosphoric acid-doped TGS (TGSP). Inhomogeneous incorporation of dopants gives rise to a distribution in coercive fields in the different growth sectors. The incorporated dopant hinders polarization switch...
Dielectric relaxation in pure and irradiated TGSP crystals
Arunmozhi, G.; Lanceros-Méndez, S.; Gomes, E. de MatosLow frequency dielectric measurements in triglycine sulpho-phosphate (TGSP) and gamma-irradiated TGSP crystals were carried out around the ferroelectric to paraelectric phase transition. The dispersion found in the ferroelectric phase cannot be explained only by a Debye equation with a single relaxation time. The ratio of the Curie constants in the para- and ferroelectric phase (C-p/C-f) for the irradiated TGSP...
| Financiadores do RCAAP | |||||||
|
|
|
|
|
|
||