Browsing by Author "Macovez, Roberto"
Now showing items 1-20 of 35
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Amorphous binary dispersions of chloramphenicol in enantiomeric pure and racemic poly-lactic acid: morphology, molecular relaxations, and controlled drug release
(2019-09-10)
Article
Open AccessWe study amorphous solid dispersions (ASDs) of the chloramphenicol antibiotic in two biodegradable polylactic acid polymers, namely a commercial sample of enantiomeric pure PLLA and a home-synthesized PDLLA copolymer, to ... -
C60 solvate with (1,1,2)-trichloroethane: dynamic statistical disorder and mixed conformation
(2016-05-27)
Article
Open AccessWe present a full characterization of the orientationally disordered cocrystal of C-60 with (1,1,2)-triChloroethane (C2H3Cl3), by means of X-ray diffraction, Raman spectroscopy, and broadband dielectric spectroscopy. Our ... -
Collective relaxation dynamics and crystallization kinetics of the amorphous Biclotymol antiseptic
(2015-11-10)
Article
Open AccessWe employ dielectric spectroscopy to monitor the relaxation dynamics and crystallization kinetics of the Biclotymol antiseptic in its amorphous phase. The glass transition temperature of the material as determined by ... -
Double primary relaxation in a highly anisotropic orientational glass-former with low-dimensional disorder
(2016-04-26)
Article
Open AccessThe freezing of the cooperative reorientational motions in orientationally disordered (OD) molecular crystals marks the so-called \glassy" transition, which may be considered a lower-dimensional version of the structural ... -
Enhancement of the physical and chemical stability of amorphous drug-polymer mixtures via cryogenic comilling
(American Chemical Society (ACS), 2018-11-27)
Article
Open AccessAmorphous dispersions of the Biclotymol antiseptic are obtained in polyvinylpyrrolidone (PVP), for different drug loadings, by comilling at temperatures below the glass transition of both components. Characterization of ... -
Formulation and characterization of mucoadhesive controlled release matrix tablets of captopril
(2017-12-01)
Article
Open AccessThe purpose of this study is to characterize controlled release matrix tablets of captopril and to find out the physicochemical properties that have an effect on the mucoadhesion process. The hydrophilic matrix tablets ... -
Genuine antiplasticizing effect of water on a glass-former drug
(Macmillan Publishers, 2017-08-07)
Article
Open AccessWater is the most important plasticizer of biological and organic hydrophilic materials, which generally exhibit enhanced mechanical softness and molecular mobility upon hydration. The enhancement of the molecular dynamics ... -
Hopping conductivity and polarization effects in a fullerene derivative salt
(2014-06-12)
Article
Restricted access - publisher's policyImpedance spectroscopy is employed to probe the frequency-dependent conductivity and dielectric response of the C60O24Na 24 fulleride. The conduction properties of this organic material match the so-called universal behavior ... -
Measurement of the dispersion of air and of refractive index anomalies by wavelength- dependent nonlinear interferometry
(2009-07-27)
Article
Open AccessWe carry out wavelength-dependent second harmonic interference experiments using thin films of an organic dye as nonlinear optical sources. While the measured difference of refractive index between the fundamental and ... -
Mixtures of m-fluoroaniline with apolar aromatic molecules: Phase behaviour, suppression of H-bonded clusters, and local H-bond relaxation dynamics
(2019-12-15)
Article
Restricted access - publisher's policyWe employ differential scanning calorimetry, IR spectroscopy, X-ray powder diffraction and dielectric spectroscopy to characterize binary mixtures of m-fluoroaniline (mFA), a rigid-molecule glass former, with two ... -
Molecular conformation in organic films from quantum chemistry ab initio calculations and second harmonic spectroscopy
(2012-11-30)
Article
Restricted access - publisher's policyIdentifying molecular species and conformations at surfaces is of interest for both catalytic and biointerfacial research. Here, we present an extinction and second harmonic spectroscopy study of films of crystal violet ... -
Molecular diffusion and dc conductivity perfectly correlated with molecular rotational dynamics in a plastic crystalline electrolyte
(2015-01-01)
Article
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Molecular ¿(2) gratings via electron-beam lithography
(2010-07)
Article
Restricted access - publisher's policyWe show that the nonlinear optical activity of an organic molecule may be quenched by electron irradiation. Exploiting this effect, we inscribe periodic χ(2) patterns in the molecular films by means of a scanning electron ... -
New approaches for the fabrication of photonic structures of nonlinear optical materials
(2009-12)
Article
Restricted access - publisher's policyWe revisited two different strategies to fabricate 1D photonic crystals of nonlinear optical dielectric materials based on ultrafast laser ablation of the surface of an RbTiOPO4 crystal, and selective etching of ferroelectric ... -
Nose temperature and anticorrelation between recrystallization kinetics and molecular relaxation dynamics in amorphous morniflumate at high pressure
(2019-07-05)
Article
Open AccessWe probe the dielectric response of the supercooled liquid phase of Morniflumate, a drug with anti-inflammatory and antipyretic properties, studying in particular the pressure and temperature dependence of the relaxation ... -
Orientational relaxations in solid (1,1,2,2)tetrachloroethane
(2016)
Article
Open AccessWe employ dielectricspectroscopy and molecular dynamic simulations to investigate the dipolar dynamics in the orientationally disordered solid phase of (1,1,2,2)tetrachloroethane. Three distinct orientational dynamics are ... -
Physical properties of organic fullerene cocrystals
(2018-01-04)
Article
Open Access -
Polymorphism with conformational isomerism and incomplete crystallization in solid ethanolamine
(2019-09-25)
Article
Open AccessWe employ calorimetry, Rietveld refinement of X-ray powder diffraction, broadband dielectric spectroscopy and molecular dynamics simulations, to investigate the phase behavior, crystal structure, dc conductivity and ... -
Protonic surface conductivity and proton space-charge relaxation in hydrated fullerol
(2017-03-09)
Article
Restricted access - publisher's policyThe ac dielectric properties of both anhydrous fullerol (C-60(OH)(24)) and hydrated fullerol with 20% water mass content are investigated by means of temperature-dependent dielectric spectroscopy. Anhydrous polycrystalline ... -
Relaxation dynamics vs crystallization kinetics in the amorphous state: the case of Stiripentol
(2017-11-06)
Article
Open AccessWith the aim of finding a correlation between the crystallization kinetics and the molecular dynamics of a substance that would allow prediction of its crystallization time as a function of temperature for a given a ...
