In the present work, polylactic acid (PLA), elastin and gelatin fibers, containing clindamycin, were prepared to test their potential application as wound dressings. They underwent release studies to ...determine the mechanism of drug release through mathematical models. The fibers have a homogeneous morphology, without pores. The studies of FTIR and thermal analysis corroborate the presence of each of the components in the fibers; the results of the feasibility tests showed encouraging percentages with a viability of 82% after 7 days of direct contact of the HUVEC cells with the membranes. Similarly, cell adhesion assays show the presence of viable and stretched cells on the fibers, the tendency of the cells to position themselves on the fibers and follow this conformation was observed. On the other hand, studies of antimicrobial activity against
S. aureus
show us that in fibers loaded with clindamycin they have inhibition halos greater than 8 mm.
A supercapacitor based on nitrile butadiene rubber substrate (NBR) and polypyrrole (PPy) was developed in this work. PPy was deposited on the surface of the substrate, NBR, which acts as a solid ...electrolyte in a sandwich arrangement, using a simple and fast in situ chemical synthesis, employing copper(II) perchlorate. The system was characterized by optical and scanning electron microscopy, infrared spectroscopy, thermogravimetry and differential scanning calorimetry. The electrochemical behavior was studied using cyclic voltammetry, chronoamperometry and galvanostatic discharge techniques. The swelling preparation method allows obtaining a suitable adhesion between the PPy and the elastomeric matrix, rendering a flexible hybrid platform for storage-energy applications. The system shows a near-reversible electrochemical behavior and specific capacitance value as high as 198.24 F g
−1
, reached at lower scan rates. This makes the sandwich arrangement PPy/NBR/PPy a promising system for versatile designs of supercapacitor devices.
Indium sulfide (In
2
S
3
) thin films were deposited on polyethylene naphthalate (PEN) by chemical bath deposition (CBD). The materials were characterized by ultraviolet (UV)–visible spectroscopy, ...x-ray photoelectron spectroscopy (XPS), energy-dispersive x-ray spectroscopy (EDX), scanning electron microscopy (SEM), and x-ray diffraction (XRD) to investigate the influence of the polymeric substrate on the resulting thin In
2
S
3
. The films showed polycrystalline (cubic and tetragonal) structure. A reduction of the ordering of the polymeric chains at the surface of the PEN was also observed, demonstrated by the appearance of two infrared bands at 1094 cm
−1
and 1266 cm
−1
. Presence of oxygen during the early stages of In
2
S
3
growth was also identified. We propose a reaction mechanism for both the equilibrium and nucleation stages. These results demonstrate that In
2
S
3
can be deposited at room temperature on a flexible substrate.
Chemical hydrogel based on poly(γ-glutamic acid) obtained from
Bacillus licheniformis (
ATCC-9945a) and using urea as a crosslinking agent was synthesized. The hydrogel was characterized by infrared ...spectroscopy, scanning electron microscopy, thermal analysis and swelling capacity. The crosslinking of the biopolymer was evidenced by changes in the intensities of signals in the infrared spectrum corresponding to amide groups, with respect to the spectrum of the pure biopolymer. Moreover, a porous structure, characteristic of hydrogels, with average pore size of 80 ± 31 μm was confirmed. The hydrogel showed a glass transition temperature of 144.5 °C and a decomposition temperature of 219 °C. The swelling ratio of the hydrogel increased with the increase of contact time with the swelling medium and pH, presenting values at equilibrium of 6.6, 13.4 and 15.3 at pH 3.6, 7.4 and 10, respectively; meanwhile, little influence of temperature on the swelling of the material was observed. Moreover, through the use of mathematical models, it is deduced that the swelling of the hydrogel in the buffer solutions occurs through lower Fickian and Fickian type mechanisms, and in deionized water an anomalous mechanism predominates.
Graphical abstract
The properties of hydroxyapatite (HAp) obtained from tilapia (Oreochromis niloticus) bones and its potential use as a dye adsorbent using methyl orange (MO) as a model dye were evaluated. HAp was ...produced by the calcination of dried tilapia bones at 900 °C for 4 h. Then, HAp was characterized using thermogravimetric (TGA) and differential thermogravimetric (dTG) analyses, Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM) and energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM), x-ray diffraction (XRD), among others. The HAp obtained was used for MO dye adsorption in a batch process. The yield of HAp was 51.6%. FTIR showed characteristic bands of functional groups of HAp OH- and (PO4)3-. FESEM images showed HAp with different morphologies and a porous surface. The EDS analysis indicated the presence of calcium and phosphorus with an atomic ratio of Ca/P of 1.60, TEM images revealed the formation of agglomerates and an average particle size of 655.1 nm. HAp and β-tricalcium phosphate (β-TCP) phases were identified through XRD. The HAp point of zero charge (pHpzc) was 9.7 indicating a possible adsorption of anionic dyes at pH< pHpzc and cationic dyes at pH> pHpzc. The HAp was able to successfully adsorb 82.6% of MO dye from aqueous solution. These findings demonstrated that the HAp obtained from tilapia (O. niloticus) bones possesses suitable properties to be used as a potential material to remove dyes.
Indium sulfide (In sub(2)S sub(3)) thin films were deposited on polyethylene naphthalate (PEN) by chemical bath deposition (CBD). The materials were characterized by ultraviolet (UV)-visible ...spectroscopy, x-ray photoelectron spectroscopy (XPS), energy-dispersive x-ray spectroscopy (EDX), scanning electron microscopy (SEM), and x-ray diffraction (XRD) to investigate the influence of the polymeric substrate on the resulting thin In sub(2)S sub(3). The films showed polycrystalline (cubic and tetragonal) structure. A reduction of the ordering of the polymeric chains at the surface of the PEN was also observed, demonstrated by the appearance of two infrared bands at 1094 cm super(-1) and 1266 cm super(-1). Presence of oxygen during the early stages of In sub(2)S sub(3) growth was also identified. We propose a reaction mechanism for both the equilibrium and nucleation stages. These results demonstrate that In sub(2)S sub(3) can be deposited at room temperature on a flexible substrate.
