Browsing Faculté des arts et des sciences – Département de chimie – Travaux et publications by Title
Now showing items 34-56 of 56
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On the importance of noncrystalline phases in semicrystalline electrospun nanofibers
(American Chemical Society, 2021-11-18)Tailoring the properties of electrospun fibers requires a detailed understanding and control of their microstructure. We investigate the structure/property relationships in fabrics of randomly aligned fibers of polylactide, a prevalent biopolymer, ... -
Orientation and partial disentanglement in individual electrospun fibers : diameter dependence and correlation with mechanical properties
(American Chemical Society, 2015-06-29)Electrospun fibers are versatile materials that exhibit unusual and tunable properties when studied at the single fiber level, including an exponential increase in modulus with a decreasing diameter toward the nanoscale. Understanding the detailed ... -
Photoactive/passive molecular glass blends : an efficient strategy to optimize azomaterials for surface relief grating inscription
(American Chemical Society, 2016-12-15): Irradiation of azomaterials causes various photophysical and photomechanical effects that can be exploited for the preparation of functional materials such as surface relief gratings (SRGs). Herein, we develop and apply an efficient strategy to ... -
Photocontrol of supramolecular azo-containing block copolymer thin films during dip-coating : toward nanoscale patterned coatings
(American Chemical Society, 2019-05-07)Dip-coating allows nanostructured block copolymer (BCP) thin film fabrication in a fast and facile one-step process. It can also be coupled with external controls, such as illumination. Herein, we expose several design principles that enable photocontrol ... -
Polarized raman analysis of polymer chain orientation in ultrafine individual nanofibers with variable low crystallinity
(American Chemical Society, 2018-10-26)Recent mechanical studies of ultrafine electrospun polymer nanofibers showed they can simultaneously possess high strength and toughness attributed to high degree of chain alignment coupled with low crystallinity. Quantitative analysis of macromolecular ... -
Pressure-induced change of d-d luminescence energies, vibronic structure and band intensities in transition metal complexes
(Taylor and Francis, 2006-08-16)The effects of hydrostatic pressure on the luminescence spectra of tetragonal transition metal complexes with nondegenerate electronic ground states are analyzed quantitatively by means of models based on potential energy surfaces defined along normal ... -
Probing interfacial interactions and dynamics of polymers enclosed in boron nitride nanotubes
(Wiley, 2021-11-23)Understanding interfacial interactions in polymer systems is crucial for their applicability for instance in adhesives and coatings. Enclosing polymers in a cylindrical volume provides a system for studying interactions dictated by a continuous ... -
Quantification and characterization of Ti-, Ce- and Ag5 nanoparticles in global surface waters and precipitation
(American Chemical Society, 2021-06-28)Nanoparticle (NP) emissions to the environment are increasing as a result of anthropogenic activities, prompting concerns for ecosystems and human health. In order to evaluate the risk of NPs, it is necessary to know their concentrations in various ... -
Quantification of ZnO nanoparticles and other Zn containing colloids in natural waters using a high sensitivity single particle ICP-MS
(Elsevier, 2019-03-08)Inductively coupled plasma mass spectrometry in single particle mode (SP-ICP-MS) is becoming a powerful tool of choice for the quantification and characterization of metallic nanoparticles (NP) at very low concentrations. Nonetheless, this technique ... -
Quantifying polymer chain orientation in strong and tough nanofibers with low crystallinity : towards next generation nanostructured superfibers
(American Chemical Society, 2019-04-19)Advanced fibers revolutionized structural materials in the second half of the 20th century. However, all high-strength fibers developed to date are brittle. Recently, pioneering simultaneous ultrahigh strength and toughness were discovered in fine (<250 ... -
Raman spectroscopy of individual poly(ethylene oxide) electrospun fibers : effect of the collector on molecular orientation
(Elsevier, 2016-09-06)Electrospun fibers are complex polymeric materials with a typical diameter of a few hundred nanometers that are often frozen in out-of-equilibrium states due to the fast solvent evaporation and high elongational forces during the process. Their ... -
Release of TiO2 nanoparticles from painted surfaces in cold climates : characterization using a high sensitivity single-particle ICP-MS
(Royal Society of Chemistry, 2020)Paints and coatings represent one of the major applications of TiO2 nanoparticles (NPs). While it has been previously shown that NPs are released from painted surfaces, there is still a lack of experimental data on their release rates under natural ... -
Sample preparation for the analysis of nanoparticles in natural waters by single particle ICP-MS
(Elsevier, 2021-11-12)With the significant increase in the production and use of nanoparticles (NP), concern is increasing over their release into their environment. Single particle inductively coupled plasma mass spectrometry (SP-ICP-MS) is emerging as one of the best ... -
Selective isotopic labeling resolves the gel-to-fluid phase transitions of the individual leaflets of a planar-supported phospholipid bilayer
(American Chemical Society, 2019-07-05)Knowledge of the thermotropic phase behavior of solid-supported bilayer lipid assemblies is essential to mimick the molecular organization and lateral fluidity of cell membranes. The gel-to-fluid phase transitions in a homologous series of single ... -
Separation, detection and characterization of nanomaterials in municipal wastewaters using hydrodynamic chromatography coupled to ICPMS and single particle ICPMS
(Springer, 2016-03-12)Engineered nanoparticles (ENP) are increasingly being incorporated into consumer products and reaching the environment at a growing rate. Unfortunately, few analytical techniques are available that allow the detection of ENP in complex environmental ... -
Smart packaging in the sustainability challenge : eumelanin as a UV-absorption enhancer of polymers
(Institute of Electrical and Electronics Engineers, 2019-09-19)The black-brown biopigment eumelanin screens the harmful ultraviolet (UV) radiation in the human skin. In industry, the absorption of plastics in the UV range is improved by the inclusion of additives. Our work reports an evaluation of the biopigment ... -
Stable amide activation of N-acetylated glycosamines for the synthesis of fused polycyclic glycomimetics
(American Chemical Society, 2024-01-02)N-Acetylation of carbohydrates is an underexplored target for chemoselective derivatization and generation of glycomimetic scaffolds. Through mild amide activation, we report that N-acetimidoyl heterocycles are stable in neutral or basic conditions yet ... -
Taming macromolecules with light : lessons learned from vibrational spectroscopy
(Wiley, 2017-09-12)Exciting new applications, from large-area nanopatterning and templating to soft light-powered robotics, are emerging from the fundamental research on light-triggered changes in macromolecular systems upon photoisomeriza-tion of azobenzene-based molecular ... -
Target and nontarget screening of PFAS in drinking water for a large-scale survey of urban and rural communities in Québec, Canada
(Elsevier, 2023-02-16)Limited monitoring data are available regarding the occurrence of emerging per- and polyfluoroalkyl substances (PFAS) in drinking water. Here, we validated an analytical procedure for 42 PFAS with individual detection limits of 0.001–0.082 ng/L. We ... -
Thermal degradation of conventional and nanoencapsulated azoxystrobin due to processing in water, spiked strawberry and incurred strawberry models
(American Chemical Society, 2022-09-21)Nanoencapsulated formulations of pesticides have been recently developed, and some products are now marketed for specific applications in agriculture. Pesticide residues present in raw agricultural products can degrade or react during food processing ... -
Time-dependent theory of electronic spectroscopy
(Elsevier, 2021)The time-dependent theory of electronic spectroscopy provides an intuitive approach to understand and quantitatively analyze absorption, luminescence and resonance Raman spectra beyond vertical transition energies. The approach can be combined with ... -
Triazine‐based molecular glasses frustrate the crystallization of barbiturates
(Royal Society of Chemistry, 2019-02-05)Hydrogen bonding is a key element of supramolecular chemistry and is often used in crystal engineering to direct crystal packing. In particular, systems where motifs with multiple hydrogen (H) bonds are present, such as the donor–acceptor–donor – ... -
Variable-pressure luminescence and Raman spectroscopy of molecular transition metal complexes : spectroscopic effects originating from small, reversible structural variations
(Royal Society of Chemistry, 2014)The past ten years have seen a significantly increasing number of published crystal structures for molecular transition metal complexes at variable pressure, providing quantitative information on structural variations. Spectroscopic measurements at ...
