Influence Of Polymer Matrices Research Articles

Influence of polymer matrices on the structural, morphological, thermal, and optical properties of PbS nanoparticles embedded in electrospun nanofibers

The development of electrospun nanomaterials with tunable optical and structural properties has significant implications for various applications. Herein, we develop a controllable and efficient strategy for in situ-grown Lead sulfide (PbS) nanoparticles (NPs) in the electrospun PVA-PVP blend nanofibers. The fibrous mats have been synthesized for different concentrations of PbS NPs grown in the PVA-PVP blend along with its parent polymers, PVA and PVP. The study uniquely enables the in-situ growth of PbS NPs within these matrices, resulting in nanofibers with tunable optical and structural properties. The synthesized PbS/Polymer nanofibers exhibit significant variation in bandgap values, ranging from 2.7 to 1.16 eV for PbS concentrations between 0.05 M and 0.2 M across all polymer matrices. Furthermore, our findings suggest that the interaction between the PbS NPs and polymer matrix does not solely result in simple additive effects. The observed results have been comprehensively analyzed, considering the intricate effects of quantum confinement.

Micromechanical modeling of barrier properties of polymer nanocomposites

Observations in barrier tests on polymer composites with flake-like nanoparticles demonstrate one-step and two-step experimental dependencies of penetrant diffusivity on volume fraction of filler. Conventional models describe the one-step monotonic reduction in the effective diffusivity, but fail to predict the two-step decay. A model is developed for the effective diffusivity of polymer nanocomposites that takes into account clustering of nanoparticles induced by an increase in their content. An advantage of the model is that it (i) predicts both one-step and two-step experimental diagrams in an unified manner, and (ii) involves only two adjustable parameters with transparent physical meaning. The model is applied to the analysis of barrier properties of composites loaded with layered silicate clays, graphene, graphene oxide and reduced graphene oxide, boron nitride and molybdenum disulfide. Good agreement is shown between the experimental data and results of simulation. The influence of polymer matrices, types and chemical modifications of nanoparticles and preparation conditions on aggregation of filler is studied numerically.

Modified Surface Relief Layer Created by Holographic Lithography: Application to Selective Sodium and Potassium Sensing.

Point-of-care diagnostics will rely upon the development of low-cost, noncomplex, and easily integrated systems in order to examine biological samples such as blood and urine obtained from the patient. The development of metal ion sensors is a subject of significant relevance for physiological samples. The level of different blood electrolytes, mainly H+, Na+, K+ and Cl− is considerably used to monitor irregular physiologies. The particular challenge in biosensing, and in fact for any other sensor, is signal differentiation between non-specifically bound material and the specific detecting of the target molecule/ion. The biosensors described in this paper are fabricated by a holographic recording of surface relief structures in a photopolymer material. The surface structures are modified by coating with either dibenzo-18-crown-6 (DC) or tetraethyl 4-tert-butylcalix[4]arene (TBC), which are embedded in a polymer matrix. Interrogation of these structures by light allows indirect measurement of the concentration of the analyte. The influence of polymer matrices with different porosities, plasticised polyvinyl chloride (PVC) and a sol-gel matrix, on the performance of the sensors for detection of K+ and Na+ is examined. Here we demonstrate a proof of concept that by using a matrix with higher porosity one can increase the sensitivity of the sensor. The results showed that the DC sensing layer provides a selective response to K+ over Na+ and the TBC modified grating is more responsive to Na+ over K+. The sensor responds to K+ and Na+ within the physiological concentration ranges.

Tuned chromic process for polydiacetylenes vesicles: the influence of polymer matrices

Thermo-sensitive poly(N-isopropylacrylamide) hydrogel was used as a matrix polymer to immobilize polydiacetylenes (PDAs) vesicles. Blue-red chromic transition of PDAs was observed at lower temperature, compared to PDAs vesicle dispersion. The tuned chromic process was due to the interaction between matrix polymer and PDAs, especially the discontinuous volume phase transitions around the lower critical solution temperature of poly(N-isopropylacrylamide).

A New Crosslinkable Oxygen Sensor Covalently Bonded into Poly(2-hydroxyethyl methacrylate)-CO-Polyacrylamide Thin Film for Dissolved Oxygen Sensing.

A new oxygen sensor, compound 2, was synthesized through a chemical modification of a popularly used oxygen sensor of platinum(II)-5,10,15,20-tetrakis-(2,3,4,5,6-pentafluorophenyl)-porphyrin (PtTFPP). The new sensor compound 2 possesses four crosslinkable methacrylate functional moieties, enabling it to be polymerized and crosslinked with other monomers for polymer sensing film (also called membrane) preparation. Using this characteristic, compound 2 was covalently bonded to hydrophilic poly(2-hydroxyethyl methacrylate)-co-polyacrylamide (referred to as PHEMA to simplify) and hydrophobic polystyrene (PS) films. To better understand the advantages and disadvantages of chemical crosslinking approaches and the influence of polymer matrices on sensing performance, PtTFPP was physically incorporated into the same PHEMA and PS matrices to compare. Response to dissolved oxygen (DO), leaching of the sensor molecules from their matrices, photostability of the sensors, and response time to DO changes were studied. It was concluded that the chemical crosslinking of the sensor compound 2 in polymer matrices: (i) alleviated the leaching problem of sensor molecules which usually occurred in the physically doped sensing systems and (ii) significantly improved sensors' photostability. The PHEMA matrix was demonstrated to be more suitable for oxygen sensing than PS, because for the same sensor molecule, the oxygen sensitivity in PHEMA film was higher than that in PS and response time to DO change in the PHEMA film was faster than that in PS. It was the first time oxygen sensing films were successfully prepared using biocompatible hydrophilic PHEMA as a matrix, which does not allow leaching of the sensor molecules from the polymer matrix, has a faster response to DO changes than that of PS, and does not present cytotoxicity to human lung adenocarcinoma epithelial cells (A549). It is expected that the new sensor compound 2 and its similar compounds with chemically crosslinking characteristics can be widely applied to generate many interesting oxygen sensing materials for studying biological phenomena.

Influence of polymer matrices on spectral properties of pyrazoloquinoline derivatives

An influence of the PMMA polymer matrices on spectral shift of principal absorption and luminescent parameters is studied. Following semi-empirical quantum chemical calculations within AM1 approach and comparing with the experimental data it was established that the PMMA matrix substantially suppresses principal absorption bands of the chromophore investigated. The photoluminescence spectra being independent of the matrices demonstrate substantial dependence on the vibration stimulated red shifts manifested in the absorption spectra.

Influence of Polymer Matrices on the Photophysical Properties of UV Absorbers

ADVERTISEMENT RETURN TO ISSUEPREVAddition/CorrectionNEXTInfluence of Polymer Matrices on the Photophysical Properties of UV AbsorbersMartin Stein, Juergen Keck, Frank Waiblinger, Anja P. Fluegge, Horst E. A. Kramer, Achim Hartschuh, Helmut Port, David Leppard, and Gerhard RytzCite this: J. Phys. Chem. A 2002, 106, 37, 8834Publication Date (Web):August 16, 2002Publication History Published online16 August 2002Published inissue 1 September 2002https://doi.org/10.1021/jp021678zCopyright © 2002 American Chemical SocietyRIGHTS & PERMISSIONSArticle Views286Altmetric-Citations-LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (6 KB) Get e-Alerts Get e-Alerts

Influence of polymer matrices on the photoelectrochemical properties of a molecular semiconductor by structural modification

AbstractThin films of phthalocyaninatozinc(II) (PcZn) have been prepared by physical vapor‐deposition or from solutions in organic solvents in mixture with poly(vinylidene fluoride) PVDF. The molecular order, i.e. the structure of the van der Waals bonded crystals, depends on the preparation technique and on the chosen matrix. By annealing the thin films or by embedding the phthalocyanine in a polymer environment, the structure is effected significantly. This is demonstrated by electronic spectra. The activities of the films have been investigated in the photoreduction of oxygen dissolved in an aqueous electrolyte. The highest sensitivities towards visible light are observed in matrices of polymers with a high dipole moment. Aside from the influence of a polar polymer towards a more favourable crystallization of PcZn an active role in the charge carrier generation process is derived from a discussion of the results within the model of molecular semiconductors which is appropriate for phthalocyanines.