39 results match your criteria: "Xerox Research Centre of Canada[Affiliation]"
Carbohydr Polym
October 2021
Department of Chemical Engineering, McMaster University, Hamilton, ON L8S 4L8, Canada. Electronic address:
A novel acylation approach suited to rapid bulk thermoplasticization of lignocellulose without solvents was previously demonstrated by the authors in benchtop batch studies. The method relies upon a benzethonium chloride/sulfuric acid functionalizing agent at low concentrations to act as a wetting agent for the wood pulp, similar to an ionic liquid, yet binds to the lignocellulose ester as a flow aid in the final thermoplastic. The present investigation evaluates the approach in a residence time-limited (45-90 s) continuous twin-screw reactor, where intensive mixing and heat were found to yield high acylation.
View Article and Find Full Text PDFACS Appl Mater Interfaces
October 2020
Department of Mechanical and Materials Engineering, Faculty of Engineering, Western University, London, Ontario, Canada N6A 3K7.
Delicate metal parts with superior electrical, mechanical, and thermal properties have attracted a lot of interest, but it is yet challenging to fabricate. Herein, a strategy of making complex metallic structures is developed in this research through integrating a bioinspired catechol-based initiator, dopamine, as an example, into the three-dimensional (3D) printing process followed by the assistance of surface modification. The wealthy catechol groups growing on the polymer enable the metal coating with a high adhesion stability.
View Article and Find Full Text PDFACS Sens
February 2020
Electrical and Computer Engineering , McMaster University, 1280 Main Street W , Hamilton , ON L8S 4K1 , Canada.
Rapid, accurate and inexpensive monitoring of water quality parameters is indispensable for continued water safety, especially in resource-limited areas. Most conventional sensing systems either can only monitor one parameter at a time or lack user-friendly on-site monitoring capabilities. A fully integrated electrochemical sensor array is an excellent solution to this barrier.
View Article and Find Full Text PDFACS Appl Mater Interfaces
June 2018
Department of Electrical and Computer Engineering , McMaster University, 1280 Main Street West , Hamilton , Ontario L8S 4K1 , Canada.
Monitoring of trace amount of acetaminophen and estrogen in drinking water is of great importance because of their potential links to gastrointestinal diseases and breast and prostate cancers. The sensitive and accurate detection of acetaminophen and estrogen requires the development of advanced sensing materials that possess appropriate number of analyte-capturing sites and suitable signal conduction path. This can be achieved by implementing appropriate chemical attachment of multiwalled carbon nanotubes (MWCNTs) and β-cyclodextrin (βCD).
View Article and Find Full Text PDFRapid Commun Mass Spectrom
February 2017
Surface Science Western, The University of Western Ontario, 999 Collip Circle, London, Ontario, N6G 0J3, Canada.
Rationale: In order to determine the degree of cross-linking on the surface and its variations in a nanometer-scale depth of organic materials, we developed an approach based on time-of-flight secondary ion mass spectrometry (TOF-SIMS), which provides rich chemical information in the form of fragment ions. TOF-SIMS is extremely surface-sensitive and capable of depth profiling with the use of a sputter ion beam to remove controllable amounts of substance.
Methods: Poly(methyl methacrylate) (PMMA) films spin-coated on a Si substrate were cross-linked using a recently developed, surface sensitive, hyperthermal hydrogen projectile bombardment technique.
Anal Chem
November 2016
Department of Electrical and Computer Engineering, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4K1, Canada.
The concentration of free chlorine used for disinfecting drinking water, recreational water, and food processing water is critical for environmental and human health conditions, and should be controlled within stipulated ranges. This report, for the first time, describes a paper-based electrochemical free chlorine sensor fabricated by hand-drawing. The electrical resistivity of a poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) chemoresistor increases when it is exposed to free chlorine in water due to oxidation reactions.
View Article and Find Full Text PDFACS Appl Mater Interfaces
February 2016
Department of Chemical Engineering, McMaster University, Hamilton, Ontario LS8 4L8, Canada.
The influence of polymer binders on the UV response of organic thin-film phototransistors (OTF-PTs) is reported. The active channel of the OTF-PTs was fabricated by blending a UV responsive 2,7-dipenty-[1]benzothieno[2,3-b][1]benzothiophene (C5-BTBT) as small molecule semiconductor and a branched unsaturated polyester (B-upe) as dielectric binder (ratio 1:1). To understand the influence of the polymer composition on the photoelectrical properties and UV response of C5-BTBT, control blends were prepared using common dielectric polymers, namely, poly(vinyl acetate) (PVAc), polycarbonate (PC), and polystyrene (PS), for comparison.
View Article and Find Full Text PDFTalanta
September 2016
Department of Electrical and Computer Engineering, McMaster University, 1280 Main Street West, Hamilton, ON, Canada L8S 4K1. Electronic address:
Highly sensitive, easy-to-fabricate, and low-cost pH sensors with small dimensions are required to monitor human bodily fluids, drinking water quality and chemical/biological processes. In this study, a low-temperature, solution-based process is developed to prepare palladium/palladium oxide (Pd/PdO) thin films for pH sensing. A precursor solution for Pd is spin coated onto pre-cleaned glass substrates and annealed at low temperature to generate Pd and PdO.
View Article and Find Full Text PDFACS Appl Mater Interfaces
November 2014
Advanced Materials Laboratory, Xerox Research Centre of Canada, Mississauga, Ontario L5K 2L1, Canada.
Graphene nanoplatelets (GNPs) were prepared from acid-treated expandable graphite using a novel method of electric heating the graphite in an evaporation chamber under high vacuum, followed by solvent exfoliation. Such prepared graphene nanoplatelets, the eGNPs, were compared to GNPs prepared from two conventional methods: thermal expansion in an isothermal oven followed by solvent exfoliation (oGNPs), and direct solvent exfoliation (sGNPs), using various characterization techniques including UV-vis spectroscopy, scanning electron microscopy, and atomic force microscopy. It was found that the eGNPs were very thin, with a thickness of 4-16 nm, and showed no oxidation.
View Article and Find Full Text PDFJ Phys Chem Lett
April 2012
§Xerox Research Centre of Canada, 2660 Speakman Drive, Mississauga, Ontario, Canada, L5K 2L1.
The first detailed study of charge transport through a liquid organic semiconductor (LOS) is reported with the goal of elucidating the effects of molecular motion on charge transport through molecular liquids. Using a liquid, silyl ether-substituted triarylamine, hole transport mobilities were obtained over a wide range of temperatures above the glass transition temperature of the material. Analysis of this data reveals that molecular motion(s) have a negligible effect on macroscopic charge transport through a molecular liquid.
View Article and Find Full Text PDFJ Am Chem Soc
March 2007
Materials Design and Integration Laboratory, Xerox Research Centre of Canada, Ontario, Canada L5K 2L1.
J Am Chem Soc
February 2007
Materials Design and Integration Laboratory, Xerox Research Centre of Canada, Mississauga, Ontario, Canada L5K 2L1.
J Am Chem Soc
April 2006
Materials Design & Integration Laboratory, Xerox Research Centre of Canada, Mississauga, Ontario, Canada.
A novel solution-processed, compositionally and structurally stable dual-layer gate dielectric composed of a UV-cured poly(4-vinyl phenol)-co-poly(methyl methacrylate) bottom layer and a thermally cross-linked poly(methyl silsesquioxane) top layer for organic thin-film transistors is described. This gate dielectric design, coupled with compatible solution-processable semiconductor and conductor materials, has enabled fabrication of all solution-processed, high-performance organic thin-film transistors on flexible substrates. High field-effect mobility and current on/off ratio, together with other desirable transistor properties, are demonstrated.
View Article and Find Full Text PDFJ Am Chem Soc
April 2006
Materials Design & Integration Laboratory, Xerox Research Centre of Canada, Mississauga, Ontario.
Oleic acid-stabilized silver nanoparticles prepared by a facile synthesis afforded highly conductive elements upon proper annealing. Regioregular polythiophene-based thin-film transistors (OTFTs) using source/drain electrodes prepared from these silver nanoparticles provided excellent field-effect characteristics, despite a significant difference between the work function of silver and the HOMO of polythiophene semiconductor. This was attributable to conductive doping of the semiconductor interface by residual oleic acid or its thermally transformed derivative from the silver electrodes, thus enabling ohmic contact formation.
View Article and Find Full Text PDFJ Am Chem Soc
March 2005
Materials Design and Integration Laboratory, Xerox Research Centre of Canada, Mississauga, Ontario, Canada L5K 2L1.
A facile synthesis of stable silver nanoparticles having a particle size of <10 nm is described. The synthesis involved reduction of silver acetate with a substituted hydrazine, such as PhNHNH2, in the presence of a 1-alkylamine, such as C16H33NH2, in toluene at 25-60 degrees C. Spin-coated thin films or printed electronic features of alkylamine-stabilized silver nanoparticles could be easily converted at 120-160 degrees C into highly conductive films or elements with conductivity of 2-4 x 104 S cm-1.
View Article and Find Full Text PDFJ Am Chem Soc
January 2005
Materials Design and Integration Laboratory, Xerox Research Centre of Canada, Mississauga, Ontario, Canada L5K 2L1.
Proper functionalization of indolo[3,2-b]carbazole led to a new class of high-performance organic semiconductors suitable for organic thin-film transistor (OTFT) applications. While 5,11-diaryl-substituted indolo[3,2-b]carbazoles without long alkyl side chains provided amorphous thin films upon vacuum deposition, those with sufficiently long alkyl side chains such as 5,11-bis(4-octylphenyl)indolo[3,2-b]carbazole self-organized readily into highly crystalline layered structures under similar conditions. OTFTs using channel semiconductors of this nature exhibited excellent field-effect properties, with mobility up to 0.
View Article and Find Full Text PDFJ Am Chem Soc
March 2004
Materials Design and Integration Laboratory, Xerox Research Centre of Canada, Mississauga, Ontario, Canada L5K 2L1.
Conjugated polymers have been widely studied as potential semiconductor materials for organic thin-film transistors (TFTs). However, they have provided functionally poor transistor properties when the TFTs are fabricated in air. We have developed a class of liquid crystalline regioregular polythiophenes, PQTs, that possess sufficient air stability to enable achievement of excellent TFT properties under ambient conditions.
View Article and Find Full Text PDFBiophys J
March 2001
Xerox Research Centre of Canada, Mississauga, Ontario L5K 2L1, Canada.
We present a meanfield theoretical approach for studying protein-solvent interactions. Starting with the partition function of the system, we develop a field theory by introducing densities for the different components of the system. At this point, protein-solvent interactions are introduced following the inhomogeneous Flory-Huggins model for polymers.
View Article and Find Full Text PDFScience
March 1999
Department of Materials Science and Engineering, McMaster University, Hamilton, Ontario, Canada. Xerox Research Centre of Canada, Mississauga, Ontario, Canada.
Studies on the long-term degradation of organic light-emitting devices (OLEDs) based on tris(8-hydroxyquinoline) aluminum (AlQ3), the most widely used electroluminescent molecule, reveal that injection of holes in AlQ3 is the main cause of device degradation. The transport of holes into AlQ3 caused a decrease in its fluorescence quantum efficiency, thus showing that cationic AlQ3 species are unstable and that their degradation products are fluorescence quenchers. These findings explain the success of different approaches to stabilizing OLEDs, such as doping of the hole transport layer, introducing a buffer layer at the hole-injecting contact, and using mixed emitting layers of hole and electron transporting molecules.
View Article and Find Full Text PDFJ Microencapsul
December 1996
Xerox Research Centre of Canada, Mississauga, Ontario, Canada.
Microcapsules containing pigment and polymer were prepared by dispersing a viscous mixture of pigment, core monomers, initiators and oil-soluble shell monomer in an aqueous solution of surfactants, forming oil-in-water droplets. Subsequently, a water-soluble shell monomer was added to these droplets, encapsulating them via interfacial (IF) polycondensation. These microcapsules were then heated for free radical (FR) polymerization of the core monomers.
View Article and Find Full Text PDFMol Biotechnol
August 1995
Xerox Research Centre of Canada, Mississauga, Ontario, Canada.
The underlying principles for zero-integrated-field electrophoresis (ZIFE) pulses and more general forward-biased pulse schemes are reviewed for one-dimensional pulsed-field gel electrophoresis (ODPFGE) separations of large DNA molecules. Detailed descriptions of materials, preparation protocols, hardware requirements, and procedures are given. A variety of gel pictures for known yeast DNA markers are shown.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
November 1993
Xerox Research Centre of Canada, Mississauga, Ontario.
The use of pulsed fields in a standard manual sequencing set-up results in the separation of > 2 kb on a single gel, as compared to 300-400 bases with a dc field. However, visual reading of the sequence from a film exposed to a pulsed-field gel is not possible for more than 800-900 bases under the best conditions. The use of image reconstruction and enhancement techniques allows the reading of the M13mp18 sequence to > 1 kb, and individual bands can be identified at > 2 kb.
View Article and Find Full Text PDFElectrophoresis
August 1993
Xerox Research Centre of Canada, Mississauga, Ontario.
Analogy between the symmetry breaking of the electrical driving force and the opposing friction force in gels using pulsed electric fields is made with the corresponding effect for polyelectrolyte coils in solution related to the molecular weight-independent charge density. The synthesis of hybrid molecules to break the symmetry of constant charge density is proposed, in which standard polypeptide end labels are attached to nucleic acid fragments. The combinatorial chemical library scheme of Brenner and Lerner (Proc.
View Article and Find Full Text PDFElectrophoresis
January 1993
Xerox Research Centre of Canada, Mississauga, Ontario.
The use of pulsed fields in manual sequencing opens up the compression zone found with a DC field and extends the range of resolution from a few hundred bases to several thousand bases. The band inversion problem is overcome with the proper pulsing conditions, and the bands are sharper than for the DC field case. Accurate visual reading is possible up to about 800-900 bases.
View Article and Find Full Text PDFElectrophoresis
August 1992
Xerox Research Centre of Canada, Mississauga, Ontario.
The effect of pulsed fields on sequencing gel electrophoresis is investigated, using DNA fragment markers ranging in size from 20 to 6557 bases. For high continuous electric fields (5000 V/55 cm) band inversion is observed in which fragments larger than 4000 bases migrate faster than those of 800-1000 bases. The use of one-dimensional pulsed field gel electrophoresis (ODPFGE) eliminates band inversion and extends the monotonic size-mobility relationship of the DNA markers up to about 4000 bases.
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