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Size Characterisation of Water-Soluble Polymers Using Asymmetrical Flow Field-Flow Fractionation

Wittgren, Bengt LU (1997)
Abstract (Swedish)
Popular Abstract in Swedish

Denna avhandling behandlar storlekskarakterisering av stora molekyler (polymerer) med en ny teknik, nämligen flödesfältflödesfraktionering (flödesFFF). Det aktuella storleksområdet som studerats i avhandlingen är intervallet mellan några få nanometer(nm) upp till en halv mikrometer (um). Storleksbestämningen med flödesFFF baseras på en separation av material med olika diffusionskoefficient. Denna separation äger rum i en tunn kanal (tjocklek 0.01 cm) där vandringstiden genom kanalen är direkt kopplad till diffusionskoefficient och därmed också storlek (hydrodynamisk radie). Det är alltså möjligt att direkt från vandringstiden (som registreras med dator/skrivare) erhålla information om radien på... (More)
Popular Abstract in Swedish

Denna avhandling behandlar storlekskarakterisering av stora molekyler (polymerer) med en ny teknik, nämligen flödesfältflödesfraktionering (flödesFFF). Det aktuella storleksområdet som studerats i avhandlingen är intervallet mellan några få nanometer(nm) upp till en halv mikrometer (um). Storleksbestämningen med flödesFFF baseras på en separation av material med olika diffusionskoefficient. Denna separation äger rum i en tunn kanal (tjocklek 0.01 cm) där vandringstiden genom kanalen är direkt kopplad till diffusionskoefficient och därmed också storlek (hydrodynamisk radie). Det är alltså möjligt att direkt från vandringstiden (som registreras med dator/skrivare) erhålla information om radien på molekylen. Denna förmåga har använts i avhandlingen för att studera storleksförändringar av amfifila polymerer i olika lösningsmedel (varierande pH, salter och salthalt)(artikel I till III). I de sista artiklarna har flödesFFF kombinerats med ett flervinkelljusspridarinstrument (MALS) för att bestämma också molvikt och gyrationsradie. Den stora fördelen med denna kombination är att fördelningar av molvikter och radier kan bestämmas, vilket är nödvändigt eftersom många polymerer innehåller blandningar av många olika storlekar. FlödesFFF kan separera dessa och sedan bestäms molvikt och radie för varje separerad fraktion med MALS-detektorn direkt efter separationskanalen. Denna kombinerade metodik är studerad och demonstrerad för några olika polysackarider (artikel IV till VI). (Less)
Abstract
Size, as expressed by molar mass, radius of gyration or hydrodynamic radius, for example, is a fundamental parameter of polymers in solution. Thus, there is a strong need for the characterisation of both the size and shape of polymers, particularly of those utilised in various industrial applications. In this thesis, a relatively novel technique, asymmetrical flow field-flow fractionation (flow FFF), was employed for the size charaterisation of water-soluble polymers of varying origin. The applicability of flow FFF for the size characterisation of a charged amphiphilic graft copolymer was tested first. The micellisation and aggregation behaviour of this copolymer was studied measuring hydrodynamic size in different salts at differing salt... (More)
Size, as expressed by molar mass, radius of gyration or hydrodynamic radius, for example, is a fundamental parameter of polymers in solution. Thus, there is a strong need for the characterisation of both the size and shape of polymers, particularly of those utilised in various industrial applications. In this thesis, a relatively novel technique, asymmetrical flow field-flow fractionation (flow FFF), was employed for the size charaterisation of water-soluble polymers of varying origin. The applicability of flow FFF for the size characterisation of a charged amphiphilic graft copolymer was tested first. The micellisation and aggregation behaviour of this copolymer was studied measuring hydrodynamic size in different salts at differing salt concentrations and pH by means of flow FFF. Hydrodynamic size was shown to increase dramatically when ionic strength was increased, due to the formation of large micelles and aggregates. Flow FFF was able here to rapidly characterise both single polymer molecules, of small hydrodynamic diameter (approximately 5 nm), and large aggregates, more than 100 nm in diameter.



Combined with a multi-angle light scattering (MALS) detector, it could also be used for determining molar mass and radius of gyration. This possibility was first demonstrated for two model polysaccharides, dextrans and pullulans, of known molar mass and polydispersity. Flow FFF - MALS provided here measurements of molar mass in good agreement with the manufacturer's data. Flow FFF - MALS was then used for the characterisation of modified celluloses and carrageenans. For these polymers, displaying a complex solution behaviour and thus very diffucult to characterise, distributions of molar mass and radius of gyration were readily obtained. The importance of choosing appropriate experimental conditions so as to avoid artifacts was clearly demonstrated. For the carrageenans, very large structures, with a molar mass of several million, were found to be eluted in a reverse elution order in flow FFF. (Less)
Please use this url to cite or link to this publication:
author
opponent
  • Dr Beckett, Ron, Monash University, Melbourne, Australia
organization
publishing date
type
Thesis
publication status
published
subject
keywords
multi-angle light scattering, molar mass distribution, aggregation, size characterisation, Asymmetrical flow FFF, water-soluble polymers, polysaccharides, Chemical technology and engineering, Kemiteknik och kemisk teknologi
pages
140 pages
publisher
Div of Technical Analytical Chemistry, Center for Chemistry and Chemical Engineering,
defense location
Center for Chemistry and Chemical Engineering, Sölveg 39, lecture hall C
defense date
1997-10-23 10:15
external identifiers
  • other:ISRN: LUTKDH/(TKAK-1016)/1-140(1997)
ISBN
91-628-2668-9
language
English
LU publication?
yes
id
1ad320dd-3bd7-40b5-9a41-c9a7bde8e7b2 (old id 29641)
date added to LUP
2007-06-14 11:53:38
date last changed
2016-09-19 08:45:03
@phdthesis{1ad320dd-3bd7-40b5-9a41-c9a7bde8e7b2,
  abstract     = {Size, as expressed by molar mass, radius of gyration or hydrodynamic radius, for example, is a fundamental parameter of polymers in solution. Thus, there is a strong need for the characterisation of both the size and shape of polymers, particularly of those utilised in various industrial applications. In this thesis, a relatively novel technique, asymmetrical flow field-flow fractionation (flow FFF), was employed for the size charaterisation of water-soluble polymers of varying origin. The applicability of flow FFF for the size characterisation of a charged amphiphilic graft copolymer was tested first. The micellisation and aggregation behaviour of this copolymer was studied measuring hydrodynamic size in different salts at differing salt concentrations and pH by means of flow FFF. Hydrodynamic size was shown to increase dramatically when ionic strength was increased, due to the formation of large micelles and aggregates. Flow FFF was able here to rapidly characterise both single polymer molecules, of small hydrodynamic diameter (approximately 5 nm), and large aggregates, more than 100 nm in diameter.<br/><br>
<br/><br>
Combined with a multi-angle light scattering (MALS) detector, it could also be used for determining molar mass and radius of gyration. This possibility was first demonstrated for two model polysaccharides, dextrans and pullulans, of known molar mass and polydispersity. Flow FFF - MALS provided here measurements of molar mass in good agreement with the manufacturer's data. Flow FFF - MALS was then used for the characterisation of modified celluloses and carrageenans. For these polymers, displaying a complex solution behaviour and thus very diffucult to characterise, distributions of molar mass and radius of gyration were readily obtained. The importance of choosing appropriate experimental conditions so as to avoid artifacts was clearly demonstrated. For the carrageenans, very large structures, with a molar mass of several million, were found to be eluted in a reverse elution order in flow FFF.},
  author       = {Wittgren, Bengt},
  isbn         = {91-628-2668-9},
  keyword      = {multi-angle light scattering,molar mass distribution,aggregation,size characterisation,Asymmetrical flow FFF,water-soluble polymers,polysaccharides,Chemical technology and engineering,Kemiteknik och kemisk teknologi},
  language     = {eng},
  pages        = {140},
  publisher    = {Div of Technical Analytical Chemistry, Center for Chemistry and Chemical Engineering,},
  school       = {Lund University},
  title        = {Size Characterisation of Water-Soluble Polymers Using Asymmetrical Flow Field-Flow Fractionation},
  year         = {1997},
}