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Papers by Andrew P Rodenhiser
Fluorescence probing and size exclusion chromatographic (SEC) techniques were applied to study co... more Fluorescence probing and size exclusion chromatographic (SEC) techniques were applied to study complexes formed in several polymer-surfactant systems. Fluorescence probing techniques measure the size, micropolarity and microviscosity of the micellar aggregates bound to the polymer. The use of the time resolved fluorescence quenching technique required writing software for data analysis. Size exclusion chromatography was adapted to measure the size of the overall polymer-surfactant complex. A multiangle laser light scattering detector and a refractometer allowed molecular weight determination without reference to elution volume.
Journal of Photochemistry and Photobiology A-chemistry, Aug 1, 2002
UV screens used to photostabilise high-yield pulp do not work as well when deposited from water a... more UV screens used to photostabilise high-yield pulp do not work as well when deposited from water as they do when deposited from organic solvents. For a water-soluble ultraviolet absorber (UVA) based on 2-hydroxybenzophenone, the water-effect is dramatic. For example, during light exposure a 78% ISO brightness paper sheet made from lignin-containing peroxide bleached softwood thermomechanical pulp (BTMP) lost 27 brightness points. A BTMP sheet treated with 0.5% by weight of the UVA 5-benzoyl-4-hydroxy-2-methoxy-benzenesulfonic acid, 1 (Uvinul MS40 TM) delivered from ethanol lost only 19 brightness points. However, a sheet treated with 0.5% of the same UVA from water lost 25 brightness points. For a benzotriazole UVA, 5-benzotriazolyl-4-hydroxy-3-sec-butyl-benzenesulfonic acid, 2 (Cibafast W TM) the adverse water-effect is smaller. Our experiments suggest several reasons for the poor performance of aqueous-delivered 1: attenuation and broadening of the absorption spectra on paper when the additive is delivered from water, disruption of the internal hydrogen bond, partial formation of phenolate ion, and changes in the distribution of the additive through the thickness of the paper sheet. This effect has been found to be general across several water-soluble benzophenone-and benzotriazole-type UVAs. One exception to the rule is found for a benzotriazole that has a PEO side chain on the hydroxyphenyl ring. Thus, choice of solvent used in testing new paper stabilisers is of central importance to stabiliser performance.
Fluorescence probing and size exclusion chromatographic (SEC) techniques were applied to study co... more Fluorescence probing and size exclusion chromatographic (SEC) techniques were applied to study complexes formed in several polymer-surfactant systems. Fluorescence probing techniques measure the size, micropolarity and microviscosity of the micellar aggregates bound to the polymer. The use of the time resolved fluorescence quenching technique required writing software for data analysis. Size exclusion chromatography was adapted to measure the size of the overall polymer-surfactant complex. A multiangle laser light scattering detector and a refractometer allowed molecular weight determination without reference to elution volume.
Surfactant science series, 1998
The Journal of Physical Chemistry B, 1999
Cationic alkylpyridinium halide surfactants have been used as quenchers of pyrene fluorescence in... more Cationic alkylpyridinium halide surfactants have been used as quenchers of pyrene fluorescence in polyelectrolyte−surfactant systems such as sodium polyacrylate−alkyltrimethylammonium halide. We use ideal mixing theory to demonstrate that for quencher molecules more strongly bound than the surfactant, the mole fraction of quencher in the micelles may be significantly greater than the mole fraction in the bulk mixture. As well, the mixed surfactant system has a lower critical aggregation concentration and a higher degree of binding than the pure surfactant system. These effects should be considered both when planning experiments and when calculating aggregation numbers. In cases of significant perturbations, the use of pyrene excimer quenching or neutral quenchers may be preferable.
Langmuir, 1993
Page 1. Langmuir 1993,9,43&443 Solubilization and Aggregation Numbers in Micellar Mix... more Page 1. Langmuir 1993,9,43&443 Solubilization and Aggregation Numbers in Micellar Mixtures of Anionic and Cationic Surfactants with Tetraethylene Glycol and Tetraethylene Glycol Dimethyl Ether D. Gerrard Marangoni,t Andrew ...
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 1999
ABSTRACT Complexation of sodium dodecyl sulphate (SDS) with a wide range of molecular weights of ... more ABSTRACT Complexation of sodium dodecyl sulphate (SDS) with a wide range of molecular weights of poly(ethylene glycol) (PEG) and poly(ethylene oxide) (PEO) has been studied by size exclusion chromatography using aqueous SDS eluent. A multi-angle laser light scattering detector and a differential refractometer were applied to give direct measurement of the molecular weight of complexes without reference to elution volume, since the latter is not a reliable indicator of the complex size. Background light scattering from micellar eluents hampered quantitative size measurements, but was minimal in sub-micellar eluent, where saturated binding was observed for polymers larger than 1000 g mol−1. Multiple peaks and voids were observed in the elution profiles of low molecular weight polymers (up to a mass of 600 g mol−1) in eluent at micellar concentrations. Several sources contribute to this behavior, including micellar chromatographic separation of the PEG oligomers due to their different distribution coefficients between the micellar and water phases. Preliminary results are reported for distribution coefficients of individual oligomers in a 600 g mol−1 PEG sample. Three distinct binding behaviors are observed with increasing degree of polymerization of PEG: no interaction for small glycols, equilibrium partitioning of intermediate oligomers in and out of micelles, and binding of micelles to the larger polymers.
ACS Symposium Series, 1992
Page 1. Chapter 11 Interaction of Alcohols and Ethoxylated Alcohols with Anionic and Cationic Mic... more Page 1. Chapter 11 Interaction of Alcohols and Ethoxylated Alcohols with Anionic and Cationic Micelles D. Gerrard Marangoni, Andrew P. Rodenhiser, Jill M. Thomas, and Jan CT Kwak1 Department of Chemistry, Dalhousie University, Halifax, Nova Scotia B3H 4J3, Canada ...
Journal of Photochemistry and Photobiology A: Chemistry, 2002
CITATIONS 15 READS 58 7 authors, including:
Biology • Chemistry • Biotechnology • Applications, 2005
Langmuir, 1993
Page 1. Langmuir 1993,9,43&443 Solubilization and Aggregation Numbers in Micellar Mix... more Page 1. Langmuir 1993,9,43&443 Solubilization and Aggregation Numbers in Micellar Mixtures of Anionic and Cationic Surfactants with Tetraethylene Glycol and Tetraethylene Glycol Dimethyl Ether D. Gerrard Marangoni,t Andrew ...
Journal of Photochemistry and Photobiology A: Chemistry, 2002
UV screens used to photostabilise high-yield pulp do not work as well when deposited from water a... more UV screens used to photostabilise high-yield pulp do not work as well when deposited from water as they do when deposited from organic solvents. For a water-soluble ultraviolet absorber (UVA) based on 2-hydroxybenzophenone, the water-effect is dramatic. For example, during light exposure a 78% ISO brightness paper sheet made from lignin-containing peroxide bleached softwood thermomechanical pulp (BTMP) lost 27 brightness points. A BTMP sheet treated with 0.5% by weight of the UVA 5-benzoyl-4-hydroxy-2-methoxy-benzenesulfonic acid, 1 (Uvinul MS40 TM ) delivered from ethanol lost only 19 brightness points. However, a sheet treated with 0.5% of the same UVA from water lost 25 brightness points. For a benzotriazole UVA, 5-benzotriazolyl-4-hydroxy-3-sec-butyl-benzenesulfonic acid, 2 (Cibafast W TM ) the adverse water-effect is smaller. Our experiments suggest several reasons for the poor performance of aqueous-delivered 1: attenuation and broadening of the absorption spectra on paper when the additive is delivered from water, disruption of the internal hydrogen bond, partial formation of phenolate ion, and changes in the distribution of the additive through the thickness of the paper sheet. This effect has been found to be general across several water-soluble benzophenone-and benzotriazole-type UVAs. One exception to the rule is found for a benzotriazole that has a PEO side chain on the hydroxyphenyl ring. Thus, choice of solvent used in testing new paper stabilisers is of central importance to stabiliser performance.
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 1999
ABSTRACT Complexation of sodium dodecyl sulphate (SDS) with a wide range of molecular weights of ... more ABSTRACT Complexation of sodium dodecyl sulphate (SDS) with a wide range of molecular weights of poly(ethylene glycol) (PEG) and poly(ethylene oxide) (PEO) has been studied by size exclusion chromatography using aqueous SDS eluent. A multi-angle laser light scattering detector and a differential refractometer were applied to give direct measurement of the molecular weight of complexes without reference to elution volume, since the latter is not a reliable indicator of the complex size. Background light scattering from micellar eluents hampered quantitative size measurements, but was minimal in sub-micellar eluent, where saturated binding was observed for polymers larger than 1000 g mol−1. Multiple peaks and voids were observed in the elution profiles of low molecular weight polymers (up to a mass of 600 g mol−1) in eluent at micellar concentrations. Several sources contribute to this behavior, including micellar chromatographic separation of the PEG oligomers due to their different distribution coefficients between the micellar and water phases. Preliminary results are reported for distribution coefficients of individual oligomers in a 600 g mol−1 PEG sample. Three distinct binding behaviors are observed with increasing degree of polymerization of PEG: no interaction for small glycols, equilibrium partitioning of intermediate oligomers in and out of micelles, and binding of micelles to the larger polymers.
The Journal of Physical Chemistry B, 1999
Fluorescence probing and size exclusion chromatographic (SEC) techniques were applied to study co... more Fluorescence probing and size exclusion chromatographic (SEC) techniques were applied to study complexes formed in several polymer-surfactant systems. Fluorescence probing techniques measure the size, micropolarity and microviscosity of the micellar aggregates bound to the polymer. The use of the time resolved fluorescence quenching technique required writing software for data analysis. Size exclusion chromatography was adapted to measure the size of the overall polymer-surfactant complex. A multiangle laser light scattering detector and a refractometer allowed molecular weight determination without reference to elution volume.
Journal of Photochemistry and Photobiology A-chemistry, Aug 1, 2002
UV screens used to photostabilise high-yield pulp do not work as well when deposited from water a... more UV screens used to photostabilise high-yield pulp do not work as well when deposited from water as they do when deposited from organic solvents. For a water-soluble ultraviolet absorber (UVA) based on 2-hydroxybenzophenone, the water-effect is dramatic. For example, during light exposure a 78% ISO brightness paper sheet made from lignin-containing peroxide bleached softwood thermomechanical pulp (BTMP) lost 27 brightness points. A BTMP sheet treated with 0.5% by weight of the UVA 5-benzoyl-4-hydroxy-2-methoxy-benzenesulfonic acid, 1 (Uvinul MS40 TM) delivered from ethanol lost only 19 brightness points. However, a sheet treated with 0.5% of the same UVA from water lost 25 brightness points. For a benzotriazole UVA, 5-benzotriazolyl-4-hydroxy-3-sec-butyl-benzenesulfonic acid, 2 (Cibafast W TM) the adverse water-effect is smaller. Our experiments suggest several reasons for the poor performance of aqueous-delivered 1: attenuation and broadening of the absorption spectra on paper when the additive is delivered from water, disruption of the internal hydrogen bond, partial formation of phenolate ion, and changes in the distribution of the additive through the thickness of the paper sheet. This effect has been found to be general across several water-soluble benzophenone-and benzotriazole-type UVAs. One exception to the rule is found for a benzotriazole that has a PEO side chain on the hydroxyphenyl ring. Thus, choice of solvent used in testing new paper stabilisers is of central importance to stabiliser performance.
Fluorescence probing and size exclusion chromatographic (SEC) techniques were applied to study co... more Fluorescence probing and size exclusion chromatographic (SEC) techniques were applied to study complexes formed in several polymer-surfactant systems. Fluorescence probing techniques measure the size, micropolarity and microviscosity of the micellar aggregates bound to the polymer. The use of the time resolved fluorescence quenching technique required writing software for data analysis. Size exclusion chromatography was adapted to measure the size of the overall polymer-surfactant complex. A multiangle laser light scattering detector and a refractometer allowed molecular weight determination without reference to elution volume.
Surfactant science series, 1998
The Journal of Physical Chemistry B, 1999
Cationic alkylpyridinium halide surfactants have been used as quenchers of pyrene fluorescence in... more Cationic alkylpyridinium halide surfactants have been used as quenchers of pyrene fluorescence in polyelectrolyte−surfactant systems such as sodium polyacrylate−alkyltrimethylammonium halide. We use ideal mixing theory to demonstrate that for quencher molecules more strongly bound than the surfactant, the mole fraction of quencher in the micelles may be significantly greater than the mole fraction in the bulk mixture. As well, the mixed surfactant system has a lower critical aggregation concentration and a higher degree of binding than the pure surfactant system. These effects should be considered both when planning experiments and when calculating aggregation numbers. In cases of significant perturbations, the use of pyrene excimer quenching or neutral quenchers may be preferable.
Langmuir, 1993
Page 1. Langmuir 1993,9,43&443 Solubilization and Aggregation Numbers in Micellar Mix... more Page 1. Langmuir 1993,9,43&443 Solubilization and Aggregation Numbers in Micellar Mixtures of Anionic and Cationic Surfactants with Tetraethylene Glycol and Tetraethylene Glycol Dimethyl Ether D. Gerrard Marangoni,t Andrew ...
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 1999
ABSTRACT Complexation of sodium dodecyl sulphate (SDS) with a wide range of molecular weights of ... more ABSTRACT Complexation of sodium dodecyl sulphate (SDS) with a wide range of molecular weights of poly(ethylene glycol) (PEG) and poly(ethylene oxide) (PEO) has been studied by size exclusion chromatography using aqueous SDS eluent. A multi-angle laser light scattering detector and a differential refractometer were applied to give direct measurement of the molecular weight of complexes without reference to elution volume, since the latter is not a reliable indicator of the complex size. Background light scattering from micellar eluents hampered quantitative size measurements, but was minimal in sub-micellar eluent, where saturated binding was observed for polymers larger than 1000 g mol−1. Multiple peaks and voids were observed in the elution profiles of low molecular weight polymers (up to a mass of 600 g mol−1) in eluent at micellar concentrations. Several sources contribute to this behavior, including micellar chromatographic separation of the PEG oligomers due to their different distribution coefficients between the micellar and water phases. Preliminary results are reported for distribution coefficients of individual oligomers in a 600 g mol−1 PEG sample. Three distinct binding behaviors are observed with increasing degree of polymerization of PEG: no interaction for small glycols, equilibrium partitioning of intermediate oligomers in and out of micelles, and binding of micelles to the larger polymers.
ACS Symposium Series, 1992
Page 1. Chapter 11 Interaction of Alcohols and Ethoxylated Alcohols with Anionic and Cationic Mic... more Page 1. Chapter 11 Interaction of Alcohols and Ethoxylated Alcohols with Anionic and Cationic Micelles D. Gerrard Marangoni, Andrew P. Rodenhiser, Jill M. Thomas, and Jan CT Kwak1 Department of Chemistry, Dalhousie University, Halifax, Nova Scotia B3H 4J3, Canada ...
Journal of Photochemistry and Photobiology A: Chemistry, 2002
CITATIONS 15 READS 58 7 authors, including:
Biology • Chemistry • Biotechnology • Applications, 2005
Langmuir, 1993
Page 1. Langmuir 1993,9,43&443 Solubilization and Aggregation Numbers in Micellar Mix... more Page 1. Langmuir 1993,9,43&443 Solubilization and Aggregation Numbers in Micellar Mixtures of Anionic and Cationic Surfactants with Tetraethylene Glycol and Tetraethylene Glycol Dimethyl Ether D. Gerrard Marangoni,t Andrew ...
Journal of Photochemistry and Photobiology A: Chemistry, 2002
UV screens used to photostabilise high-yield pulp do not work as well when deposited from water a... more UV screens used to photostabilise high-yield pulp do not work as well when deposited from water as they do when deposited from organic solvents. For a water-soluble ultraviolet absorber (UVA) based on 2-hydroxybenzophenone, the water-effect is dramatic. For example, during light exposure a 78% ISO brightness paper sheet made from lignin-containing peroxide bleached softwood thermomechanical pulp (BTMP) lost 27 brightness points. A BTMP sheet treated with 0.5% by weight of the UVA 5-benzoyl-4-hydroxy-2-methoxy-benzenesulfonic acid, 1 (Uvinul MS40 TM ) delivered from ethanol lost only 19 brightness points. However, a sheet treated with 0.5% of the same UVA from water lost 25 brightness points. For a benzotriazole UVA, 5-benzotriazolyl-4-hydroxy-3-sec-butyl-benzenesulfonic acid, 2 (Cibafast W TM ) the adverse water-effect is smaller. Our experiments suggest several reasons for the poor performance of aqueous-delivered 1: attenuation and broadening of the absorption spectra on paper when the additive is delivered from water, disruption of the internal hydrogen bond, partial formation of phenolate ion, and changes in the distribution of the additive through the thickness of the paper sheet. This effect has been found to be general across several water-soluble benzophenone-and benzotriazole-type UVAs. One exception to the rule is found for a benzotriazole that has a PEO side chain on the hydroxyphenyl ring. Thus, choice of solvent used in testing new paper stabilisers is of central importance to stabiliser performance.
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 1999
ABSTRACT Complexation of sodium dodecyl sulphate (SDS) with a wide range of molecular weights of ... more ABSTRACT Complexation of sodium dodecyl sulphate (SDS) with a wide range of molecular weights of poly(ethylene glycol) (PEG) and poly(ethylene oxide) (PEO) has been studied by size exclusion chromatography using aqueous SDS eluent. A multi-angle laser light scattering detector and a differential refractometer were applied to give direct measurement of the molecular weight of complexes without reference to elution volume, since the latter is not a reliable indicator of the complex size. Background light scattering from micellar eluents hampered quantitative size measurements, but was minimal in sub-micellar eluent, where saturated binding was observed for polymers larger than 1000 g mol−1. Multiple peaks and voids were observed in the elution profiles of low molecular weight polymers (up to a mass of 600 g mol−1) in eluent at micellar concentrations. Several sources contribute to this behavior, including micellar chromatographic separation of the PEG oligomers due to their different distribution coefficients between the micellar and water phases. Preliminary results are reported for distribution coefficients of individual oligomers in a 600 g mol−1 PEG sample. Three distinct binding behaviors are observed with increasing degree of polymerization of PEG: no interaction for small glycols, equilibrium partitioning of intermediate oligomers in and out of micelles, and binding of micelles to the larger polymers.
The Journal of Physical Chemistry B, 1999