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Bret J Chisholm - One of the best experts on this subject based on the ideXlab platform.
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combinatorial materials research applied to the development of new surface coatings xiii an investigation of polysiloxane antimicrobial coatings containing tethered quaternary ammonium salt groups
ACS Combinatorial Science, 2009Co-Authors: Partha Majumdar, Nathan Gubbins, David A Christianson, Shane J Stafslien, Justin Daniels, Lyndsi Vanderwal, James Bahr, Bret J ChisholmAbstract:High-throughput biological assays were used to develop structure - antimicrobial relationships for polysiloxane coatings containing chemically bound (tethered) quaternary ammonium salt (QAS) moieties. The QAS-functional Polysiloxanes were derived from solution blends of a silanol-terminated polydimethylsiloxane, a trimethoxysilane-functional QAS (QAS-TMS), and methylacetoxysilane. Since the QAS moieties provide antimicrobial activity through interaction with the microorganism cell wall, most of the compositional variables that were investigated were associated with the chemical structure of the QAS-TMS. Twenty different QAS-TMS were synthesized for the study and the antimicrobial activity of sixty unique polysiloxane coatings derived from these QAS-TMS determined toward Escherichia coli, Staphylococcus aureus, and Candida albicans. The results of the study showed that essentially all of the compositional variables significantly influenced antimicrobial activity. Surface characterization of these moisture-...
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combinatorial materials research applied to the development of new surface coatings xiii an investigation of polysiloxane antimicrobial coatings containing tethered quaternary ammonium salt groups
ACS Combinatorial Science, 2009Co-Authors: Partha Majumdar, Elizabeth Lee, Nathan Gubbins, David A Christianson, Shane J Stafslien, Justin Daniels, Lyndsi Vanderwal, James Bahr, Bret J ChisholmAbstract:High-throughput biological assays were used to develop structure - antimicrobial relationships for polysiloxane coatings containing chemically bound (tethered) quaternary ammonium salt (QAS) moieties. The QAS-functional Polysiloxanes were derived from solution blends of a silanol-terminated polydimethylsiloxane, a trimethoxysilane-functional QAS (QAS-TMS), and methylacetoxysilane. Since the QAS moieties provide antimicrobial activity through interaction with the microorganism cell wall, most of the compositional variables that were investigated were associated with the chemical structure of the QAS-TMS. Twenty different QAS-TMS were synthesized for the study and the antimicrobial activity of sixty unique polysiloxane coatings derived from these QAS-TMS determined toward Escherichia coli, Staphylococcus aureus, and Candida albicans. The results of the study showed that essentially all of the compositional variables significantly influenced antimicrobial activity. Surface characterization of these moisture-...
Partha Majumdar - One of the best experts on this subject based on the ideXlab platform.
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The utilization of specific interactions to enhance the mechanical properties of polysiloxane coatings
Journal of Coatings Technology Research, 2010Co-Authors: Partha Majumdar, Christy Gallagher-lein, Elizabeth Lee, Nathan Gubbins, Bret Mayo, Jongsoo Kim, Brian J ChisholmAbstract:Moisture-curable Polysiloxanes were modified with ionic groups to enable specific interactions between the polysiloxane matrix and silica nanoparticle reinforcement. A trimethoxysilane-functional quaternary ammonium salt (QAS) was used to modify the polysiloxane matrix. A comparison of the mechanical properties of coatings containing QAS modification to analogous coatings without QAS modification showed that QAS modification resulted in a dramatic improvement in mechanical properties of silica nanoparticlereinforced coatings. QAS modification provided major enhancements in both tensile modulus and toughness. The coatings were characterized using positron annihilation spectroscopy, photo-acoustic FT-IR, differential scanning calorimetry, transmission electron microscope, and atomic force microscopy. The characterization results suggested that the QAS moieties present in the polysiloxane matrix undergo specific interactions with the surface of silica nanoparticles enabling an enhancement in interfacial adhesion between the polymer matrix and the nanoparticles. Most likely, the specific interaction that provided the enhanced mechanical properties was an ion–dipole interaction involving silanol groups present on the surface of the silica nanoparticles. The enhanced modulus and toughness of these polysiloxane materials may enable their application as a fouling-release coating for ship hulls, since current polysiloxane-based fouling release coatings suffer from poor mechanical properties and durability.
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combinatorial materials research applied to the development of new surface coatings xiii an investigation of polysiloxane antimicrobial coatings containing tethered quaternary ammonium salt groups
ACS Combinatorial Science, 2009Co-Authors: Partha Majumdar, Nathan Gubbins, David A Christianson, Shane J Stafslien, Justin Daniels, Lyndsi Vanderwal, James Bahr, Bret J ChisholmAbstract:High-throughput biological assays were used to develop structure - antimicrobial relationships for polysiloxane coatings containing chemically bound (tethered) quaternary ammonium salt (QAS) moieties. The QAS-functional Polysiloxanes were derived from solution blends of a silanol-terminated polydimethylsiloxane, a trimethoxysilane-functional QAS (QAS-TMS), and methylacetoxysilane. Since the QAS moieties provide antimicrobial activity through interaction with the microorganism cell wall, most of the compositional variables that were investigated were associated with the chemical structure of the QAS-TMS. Twenty different QAS-TMS were synthesized for the study and the antimicrobial activity of sixty unique polysiloxane coatings derived from these QAS-TMS determined toward Escherichia coli, Staphylococcus aureus, and Candida albicans. The results of the study showed that essentially all of the compositional variables significantly influenced antimicrobial activity. Surface characterization of these moisture-...
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combinatorial materials research applied to the development of new surface coatings xiii an investigation of polysiloxane antimicrobial coatings containing tethered quaternary ammonium salt groups
ACS Combinatorial Science, 2009Co-Authors: Partha Majumdar, Elizabeth Lee, Nathan Gubbins, David A Christianson, Shane J Stafslien, Justin Daniels, Lyndsi Vanderwal, James Bahr, Bret J ChisholmAbstract:High-throughput biological assays were used to develop structure - antimicrobial relationships for polysiloxane coatings containing chemically bound (tethered) quaternary ammonium salt (QAS) moieties. The QAS-functional Polysiloxanes were derived from solution blends of a silanol-terminated polydimethylsiloxane, a trimethoxysilane-functional QAS (QAS-TMS), and methylacetoxysilane. Since the QAS moieties provide antimicrobial activity through interaction with the microorganism cell wall, most of the compositional variables that were investigated were associated with the chemical structure of the QAS-TMS. Twenty different QAS-TMS were synthesized for the study and the antimicrobial activity of sixty unique polysiloxane coatings derived from these QAS-TMS determined toward Escherichia coli, Staphylococcus aureus, and Candida albicans. The results of the study showed that essentially all of the compositional variables significantly influenced antimicrobial activity. Surface characterization of these moisture-...
Julian Chojnowski - One of the best experts on this subject based on the ideXlab platform.
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polysiloxane cationic biocides with imidazolium salt ims groups synthesis and antibacterial properties
European Polymer Journal, 2009Co-Authors: Urszula Mizerska, Julian Chojnowski, Witold Fortuniak, R Halasa, A Konopacka, W WerelAbstract:Abstract Novel Polysiloxanes with pendant biocidal N,N′-dialkylimidazolium salt (ImS) groups were synthesized and compared with Polysiloxanes bearing conventional biocidal quaternary ammonium salt (QAS) groups. The bacteriostatic power of these polymers was tested and compared under the same conditions in aqueous solution against two common strains of Gram positive bacteria and three strains of Gram negative bacteria. These new ImS containing polymers exhibited high antibacterial potency against all bacteria studied, similar to those substituted with QAS groups. The advantage of the imidazolium substituted polysiloxane stems from its higher thermal stability, as compared with the quaternary alkylammonium functionalized polymer, as demonstrated by thermogravimetric studies.
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3-Chloropropyl Functionalized Dendrigraft Polysiloxanes and Dendritic Polyelectrolytes
Macromolecules, 2007Co-Authors: Julian Chojnowski, Witold Fortuniak, M. Ścibiorek, Krystyna Rozga-wijas, And Agnieszka Grzelka, Urszula MizerskaAbstract:Dendrigraft Polysiloxanes bearing 3-chloropropyl functional groups pendant to the polymer branches of the last generation were synthesized by the graft on graft method. First, branched Polysiloxanes of various topologies, star, comb, and dendritic functionalized with pendant vinyl groups, were prepared. Hydrosilylation by dimethylchlorosilane transformed these groups into silyl chloride functions. Living Polysiloxanes obtained by the anionic ring-opening polymerization of 2,4,6-tri-3-chloropropyl-2,4,6-trimethylcyclotrisiloxane were terminated on these silyl chloride groups which resulted in the grafting of the 3-chloropropyl functionalized polysiloxane on the branched polysiloxane core. The 3-chloropropyl groups on the dendrigraft were further used for the quaternization of dimethyloctylamine, 2-hydroxyethyldimethylamine, and triethylamine producing quaternary ammonium salt (QAS) groups. Dendrigrafts having an ionic corona and relatively hydrophobic core were synthesized. Preliminary investigations of th...
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Polysiloxanes with chlorobenzyl groups as precursors of new organic silicone materials
Journal of Polymer Science Part A, 2004Co-Authors: Krzysztof Kazmierski, Nicolae Hurduc, Georges Sauvet, Julian ChojnowskiAbstract:Various Polysiloxanes bearing chlorobenzyl side groups were synthesized by the hydrolytic polycondensation of the 73:27 mol/mol mixture of (2-(4-chlorometh- ylphenyl)ethyl) methyldichlorosilane and (1-(4-chloromethylphenyl)ethyl) methyldi- chlorosilane followed by the cationic equilibration or coequilibration with octamethyl- cyclotetrasiloxane, D4. 1,3-Divinyltetramethyl-disiloxane was used as the chain end blocker to obtain a vinyl-Si ended chlorobenzyl-substituted polysiloxane. In some cases, the polymer was additionally treated with dimethylvinylchlorosilane to achieve full substitution of chain ends by the vinyl group. Cohydrolysis of the chlorobenzylic monomer mixture with dimethyldichlorosilane was also practiced. Multiblock copoly- mers were obtained by polyhydrosilylation of the ,-divinylsilyl chlorobenzyl-substi- tuted Polysiloxanes with ,-dihydrosilyl polydimethylsiloxanes. All these polymers and copolymers containing reactive chlorobenzylic groups were demonstrated to be convenient precursors of functional Polysiloxanes of potential practical use. Some specific functional groups, such as quaternary ammonium salt groups of biocidal activ- ity or azobenzene groups making the polymer sensitive to external stimuli by light, may be readily generated on polysiloxane under mild conditions. The chlorobenzylic substi- tuted Polysiloxanes may be also used as macroinitiators of the atom transfer radical polymerization, to obtain Polysiloxanes with grafted organic polymers, such as styrene, 4-chloromethylstyrene, and n-butylacrylate. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 1682-1692, 2004
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synthesis of branched Polysiloxanes with controlled branching and functionalization by anionic ring opening polymerization
Macromolecules, 2003Co-Authors: Julian Chojnowski, Marek Cypryk, Witold Fortuniak, And M ścibiorek, Krystyna RozgawijasAbstract:Functionalized branched Polysiloxanes with star-branched, comb-branched and dendritic-branched topologies were synthesized. The branched macromolecules were generated by coupling of reactive blocks using a grafting technique (ACS Polym. Prepr. 2001, 42, 227; ACS Symp. Ser. 2003, 838, Chapter 2). The living anionic ring-opening polymerization (ROP) of vinyl-substituted cyclotrisiloxanes (ViMeSiO)3, V3, and, VD2, and the copolymerization of these monomers with hexamethylcyclotrisiloxane, D3, was explored to obtain reactive blocks. Termination of the living polymer, having a lithium silanolate end group, on a reactive core containing SiCl groups led to the grafting of living polysiloxane on the core. Transformation of vinyl groups in the polymer into the reactive SiCl groups by hydrosilylation with Me2HSiCl made possible the grafting of a successive generation of branches. The reactive blocks of high and low density of the precursor vinyl group were obtained by the polymerization of monomers V3 and VD2, resp...
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biocidal polymers active by contact v synthesis of Polysiloxanes with biocidal activity
Journal of Applied Polymer Science, 2000Co-Authors: G Sauvet, S Dupond, Krzysztof Kazmierski, Julian ChojnowskiAbstract:Polysiloxanes with 3-(alkyldimethylammonio)propyl pendant groups were synthesized by quaternization of n-octyldimethylamine or n-dodecyldimethylamine with linear Polysiloxanes containing 3-chloropropyl groups and/or 3-bromopropyl groups attached to silicon atoms. The precursor Polysiloxanes, poly[(3-chloropropyl)methylsiloxane] homopolymer and various copolymers containing (3-halogenopropyl)methylsiloxane and dimethylsiloxane units, were obtained by equilibrium cationic polymerization of linear and cyclic siloxanes with (3-halogenopropyl)methylsiloxane units. The Polysiloxanes bearing quaternary ammonium salts (QAS) showed bactericidal activity against bacteria such as Escherichia coli and Aeromonas hydrophila when incorporated in a polysiloxane network. The activity was retained after 66 days of immersion in water. The QAS-containing Polysiloxanes are also active in aqueous solution. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 1005–1012, 2000
Nathan Gubbins - One of the best experts on this subject based on the ideXlab platform.
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The utilization of specific interactions to enhance the mechanical properties of polysiloxane coatings
Journal of Coatings Technology Research, 2010Co-Authors: Partha Majumdar, Christy Gallagher-lein, Elizabeth Lee, Nathan Gubbins, Bret Mayo, Jongsoo Kim, Brian J ChisholmAbstract:Moisture-curable Polysiloxanes were modified with ionic groups to enable specific interactions between the polysiloxane matrix and silica nanoparticle reinforcement. A trimethoxysilane-functional quaternary ammonium salt (QAS) was used to modify the polysiloxane matrix. A comparison of the mechanical properties of coatings containing QAS modification to analogous coatings without QAS modification showed that QAS modification resulted in a dramatic improvement in mechanical properties of silica nanoparticlereinforced coatings. QAS modification provided major enhancements in both tensile modulus and toughness. The coatings were characterized using positron annihilation spectroscopy, photo-acoustic FT-IR, differential scanning calorimetry, transmission electron microscope, and atomic force microscopy. The characterization results suggested that the QAS moieties present in the polysiloxane matrix undergo specific interactions with the surface of silica nanoparticles enabling an enhancement in interfacial adhesion between the polymer matrix and the nanoparticles. Most likely, the specific interaction that provided the enhanced mechanical properties was an ion–dipole interaction involving silanol groups present on the surface of the silica nanoparticles. The enhanced modulus and toughness of these polysiloxane materials may enable their application as a fouling-release coating for ship hulls, since current polysiloxane-based fouling release coatings suffer from poor mechanical properties and durability.
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combinatorial materials research applied to the development of new surface coatings xiii an investigation of polysiloxane antimicrobial coatings containing tethered quaternary ammonium salt groups
ACS Combinatorial Science, 2009Co-Authors: Partha Majumdar, Nathan Gubbins, David A Christianson, Shane J Stafslien, Justin Daniels, Lyndsi Vanderwal, James Bahr, Bret J ChisholmAbstract:High-throughput biological assays were used to develop structure - antimicrobial relationships for polysiloxane coatings containing chemically bound (tethered) quaternary ammonium salt (QAS) moieties. The QAS-functional Polysiloxanes were derived from solution blends of a silanol-terminated polydimethylsiloxane, a trimethoxysilane-functional QAS (QAS-TMS), and methylacetoxysilane. Since the QAS moieties provide antimicrobial activity through interaction with the microorganism cell wall, most of the compositional variables that were investigated were associated with the chemical structure of the QAS-TMS. Twenty different QAS-TMS were synthesized for the study and the antimicrobial activity of sixty unique polysiloxane coatings derived from these QAS-TMS determined toward Escherichia coli, Staphylococcus aureus, and Candida albicans. The results of the study showed that essentially all of the compositional variables significantly influenced antimicrobial activity. Surface characterization of these moisture-...
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combinatorial materials research applied to the development of new surface coatings xiii an investigation of polysiloxane antimicrobial coatings containing tethered quaternary ammonium salt groups
ACS Combinatorial Science, 2009Co-Authors: Partha Majumdar, Elizabeth Lee, Nathan Gubbins, David A Christianson, Shane J Stafslien, Justin Daniels, Lyndsi Vanderwal, James Bahr, Bret J ChisholmAbstract:High-throughput biological assays were used to develop structure - antimicrobial relationships for polysiloxane coatings containing chemically bound (tethered) quaternary ammonium salt (QAS) moieties. The QAS-functional Polysiloxanes were derived from solution blends of a silanol-terminated polydimethylsiloxane, a trimethoxysilane-functional QAS (QAS-TMS), and methylacetoxysilane. Since the QAS moieties provide antimicrobial activity through interaction with the microorganism cell wall, most of the compositional variables that were investigated were associated with the chemical structure of the QAS-TMS. Twenty different QAS-TMS were synthesized for the study and the antimicrobial activity of sixty unique polysiloxane coatings derived from these QAS-TMS determined toward Escherichia coli, Staphylococcus aureus, and Candida albicans. The results of the study showed that essentially all of the compositional variables significantly influenced antimicrobial activity. Surface characterization of these moisture-...
David A Christianson - One of the best experts on this subject based on the ideXlab platform.
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combinatorial materials research applied to the development of new surface coatings xiii an investigation of polysiloxane antimicrobial coatings containing tethered quaternary ammonium salt groups
ACS Combinatorial Science, 2009Co-Authors: Partha Majumdar, Nathan Gubbins, David A Christianson, Shane J Stafslien, Justin Daniels, Lyndsi Vanderwal, James Bahr, Bret J ChisholmAbstract:High-throughput biological assays were used to develop structure - antimicrobial relationships for polysiloxane coatings containing chemically bound (tethered) quaternary ammonium salt (QAS) moieties. The QAS-functional Polysiloxanes were derived from solution blends of a silanol-terminated polydimethylsiloxane, a trimethoxysilane-functional QAS (QAS-TMS), and methylacetoxysilane. Since the QAS moieties provide antimicrobial activity through interaction with the microorganism cell wall, most of the compositional variables that were investigated were associated with the chemical structure of the QAS-TMS. Twenty different QAS-TMS were synthesized for the study and the antimicrobial activity of sixty unique polysiloxane coatings derived from these QAS-TMS determined toward Escherichia coli, Staphylococcus aureus, and Candida albicans. The results of the study showed that essentially all of the compositional variables significantly influenced antimicrobial activity. Surface characterization of these moisture-...
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combinatorial materials research applied to the development of new surface coatings xiii an investigation of polysiloxane antimicrobial coatings containing tethered quaternary ammonium salt groups
ACS Combinatorial Science, 2009Co-Authors: Partha Majumdar, Elizabeth Lee, Nathan Gubbins, David A Christianson, Shane J Stafslien, Justin Daniels, Lyndsi Vanderwal, James Bahr, Bret J ChisholmAbstract:High-throughput biological assays were used to develop structure - antimicrobial relationships for polysiloxane coatings containing chemically bound (tethered) quaternary ammonium salt (QAS) moieties. The QAS-functional Polysiloxanes were derived from solution blends of a silanol-terminated polydimethylsiloxane, a trimethoxysilane-functional QAS (QAS-TMS), and methylacetoxysilane. Since the QAS moieties provide antimicrobial activity through interaction with the microorganism cell wall, most of the compositional variables that were investigated were associated with the chemical structure of the QAS-TMS. Twenty different QAS-TMS were synthesized for the study and the antimicrobial activity of sixty unique polysiloxane coatings derived from these QAS-TMS determined toward Escherichia coli, Staphylococcus aureus, and Candida albicans. The results of the study showed that essentially all of the compositional variables significantly influenced antimicrobial activity. Surface characterization of these moisture-...