Gel‐permeation chromatography: X. Molecular weight detection by low‐angle laser light scattering

Ouano, A. C.; Kaye, Wilbur

doi:10.1002/pol.1974.170120602

Cited by 118 publications

(31 citation statements)

References 12 publications

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“…[52] Low-angle laser light scattering (LALLS) uses an angle small enough to consider that the form factor is equal to 1 (there is however a critical molecular weight above which P(u) decreases to values significantly below 1). [53] Triple detection uses the 908 angle, RALLS, and calculates the form factor using relations given by Flory [49,51,54] PðuÞ ¼ 2 e Àx À ð1 À xÞ…”

Section: Expression For the Signal Of The Viscometermentioning

confidence: 99%

Theory of Multiple‐Detection Size‐Exclusion Chromatography of Complex Branched Polymers

Gaborieau

Gilbert

Gray‐Weale

et al. 2007

Macro Theory & Simulations

109

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SEC separates complex branched polymers by hydrodynamic volume, rather than by molecular weight or branching characteristics. Equations relating the response of different types of detectors are derived including band broadening, by defining a distribution function N′(M,Vh), the number of chains with molecular weight M and hydrodynamic volume Vh. While the true molecular weight distribution of complex polymers cannot be determined by SEC, irrespective of the detector used, the formalism enables multiple detection SEC data to be processed to both analyze the polymer sample and reveal mechanistic information about polymer synthesis. The formalism also shows how the true weight‐ and number‐average molecular weight, $\overline M _{\rm w}$ and $\overline M _{\rm n}$, can be obtained from correct processing of the hydrodynamic volume distributions.

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Section: Expression For the Signal Of The Viscometermentioning

confidence: 99%

Theory of Multiple‐Detection Size‐Exclusion Chromatography of Complex Branched Polymers

Gaborieau

Gilbert

Gray‐Weale

et al. 2007

Macro Theory & Simulations

109

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“…Although it was not incorporated in this study, high-precision measurements on samples with wide distributions require that the variation of Ai with molecular weight be ~onsidered.~ Once Mi has been calculated at uniform intervals on the elution curve, the molecular weight averages may be calculated in the conventional manner, namely, Mn = Zci/Z(ci/Mi) (8) MW = Z c i M i / Z~i (9) Mz = ZciMi2/ZciMi (10) As noted by 0 u a n 0 ,~ the polydispersity index Mw/Mn obtained by LALLSP/GPC analysis will be less than the true value. Due to the finite resolution of the GPC column, the Mi values do not represent monodisperse fractions.…”

Section: )mentioning

confidence: 99%

Measurement of the absolute molecular weight and molecular weight distribution of polyolefins using low‐angle laser light scattering

MacRury¹,

McConnell

1979

J of Applied Polymer Sci

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SynopsisBy connecting a low-angle laser light scattering photometer (LALLSP) on line with a high-temperature gel permeation chromatograph (GPC), molecular weight distributions were determined for three polyethylene standards (two high density and one low density) without resorting to column calibration procedures. In addition, the absolute weight-average molecular weight and second virial coefficients of four polyethylene standards (three high density and one low density) were obtained using low-angle laser light scattering. The molecular weights measured were in excellent agreement with those specified by the National Bureau of Standards, For the low density material, a microgel fraction was detected by the on-line LALLSP but not by the conventional GPC detector. This resulted in a z-average molecular weight of over 3 X 106 daltons, an order of magnitude greater than that determined by conventional GPC techniques.

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“…The Mark-Houwink constants used in these calculations were obtained from light scattering/ intrinsic viscosity measurements; details of this technique are described elsewhere [18]. The applicability of the universal calibration method for estimating the molecular weights from the GPC chromatogram was verified by comparing the values of M w obtained by G PC with those obtained by a low angle light scattering technique [19]. • Resist evaluation Resist films (1 f£m thick) were spin-coated on Si0 2 surfaces from seven percent solutions in chlorobenzene with a Headway Research Model EC-IO 1 spinner.…”

Section: • Molecular Weight Characterizationmentioning

confidence: 99%

Parameters Affecting the Electron Beam Sensitivity of Poly(methyl methacrylate)

et al. 1977

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Poly(methyl methacrylate), PMMA, is used as a model polymer to determine quantitatively the effect of molecular weight, molecular weight distribution, and tacticity on electron beam sensitivity. The heterotactic, syndiotactic, and isotactic stereoforms of PMMA were synthesized with molecular weights ranging from 10 4 to 10 7 and dispersivities from 1.2 to about 10. The G-values as determined by gamma radiation are about 1.3 and are independent of the three parameters. However, the solubility rate of PMMA is very dependent on the tacticity, and the relative solubility rates are in the order syndiotactic < heterotactic-s isotactic. The weightaverage molecular weight ratio was found to give a better correlation with solubility rate ratio than the number-average molecular weight ratio. The molecular size of the developer solvent was shown to have a much greater effect on the solubility rate than the molecular weight of the resist. An optimal developer solvent for PMMA can be systematically selected from a homologous series of nalkyl acetates which enhance the resist sensitivity.

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Gel‐permeation chromatography: X. Molecular weight detection by low‐angle laser light scattering

Cited by 118 publications

References 12 publications

Theory of Multiple‐Detection Size‐Exclusion Chromatography of Complex Branched Polymers

Theory of Multiple‐Detection Size‐Exclusion Chromatography of Complex Branched Polymers

Measurement of the absolute molecular weight and molecular weight distribution of polyolefins using low‐angle laser light scattering

Parameters Affecting the Electron Beam Sensitivity of Poly(methyl methacrylate)

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