Specific refractive index increments of polymer solutions. Part I. Literature values

Huglin, Malcolm B.

doi:10.1002/app.1965.070091219

Cited by 53 publications

(12 citation statements)

References 224 publications

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“…A cone-and-plate rheometer (Rheometrics Mechanical Spectrometer, marketed by IMASS, Inc., Accord, Mass., described by Macosko and Staritas) was used with a cone 72 mm in diameter and a cone angle of 0.04 radians. Both viscosity (7) and primary normal stress difference (PI1 -P22) were measured at room temperature (controlled to 73°F and 55y0 relative humidity), precautions being taken to prevent evaporation, as described earlier. '…”

Section: Viscoelastic Measurementsmentioning

confidence: 99%

Dispersions or solutions? A mechanism for certain thickening agents

Taylor

Bagley

1974

J of Applied Polymer Sci

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SynopsisHydrolyzed starch-polyacrylonitrile (H-SPAN) graft copolymers form highly viscoelastic mixtures with water, even at concentrations less than 1% by weight. I n many ways these mixtures behave like ordinary polyelectrolyte solutions, but dilution experiments revealed that linear reduced viscosity-concentration plots could not be obtained even under ostensibly isoionic dilution conditions. This result, combined with a determination of gel content from centrifugation studies, led t o the conclusion that high viscosity H-SPAN water mixtures consist of swollen, deformable gel particles closely packed in intimate contact. Under high dilution or at high ionic strength conditions, the gel particles no longer are tight,ly packed, solvent is present in excess, the viscosity drops precipitously, and the thickening action effectively disappears. For comparative purposes, a commercial thickening agent (Carbopol941) was examined and found to act in the same way. All reduced viscosity-concentration curves obtained by dilution, either with salt solutions or water, can be shifted to a single normalized reduced visc0sit.y plot. This shift is done by using as the concentration variable the quantity c&, where c is the polyelectrolyte concentration and Q is the swelling which the gel particles undergo in an excess of solvent at the corresponding total ionic strength of the solution of concentration c.

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Section: Viscoelastic Measurementsmentioning

confidence: 99%

Dispersions or solutions? A mechanism for certain thickening agents

Taylor

Bagley

1974

J of Applied Polymer Sci

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“…For the low-@, and high-%?, PS of known 2 1 and @Z (Table I), the h12 and Qvalues were evaluated from earlier reports,12J3 respectively. In the studies referred to, monodisperse samples were examined and the gyration radius (or the distance between the ends of a coil is proportional to the initial slope of F ( 8 ) . With systems as highly polydisperse as the present ones, the curvature, in the angular range inaccessible to measurements, is crucial for the determination of 2.…”

Section: Resultsmentioning

confidence: 99%

Light-scattering studies on solutions of high and low molecular weight polystyrene mixtures used as models of microgel-containing solutions

Strazielle

Członkowska‐Kohutnicka

1978

J. Appl. Polym. Sci.

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SynopsisDiluted solutions of linear polystyrene (PS) in tolueneand dioxan5were studied by the lightscattering method. The solutes were mixtures of high-M, and low-M, PS. The dissolved PS mixtures were regarded as polymer solutions containing microgels, the high-& PS being looked upon as the microgel counterpart. The calculation method as proposed by Strazielle' and Burchard' was used to evaluate the microgel percentage and particle sizeEhereby the method could be verified against mixtures with well-known weight composition and (rg2)lI2. The (rg2)l12 values evaluated for the mixtures from the experimental data were compared with thosGtimated from the molecular weights of the components, their weight concentrations, and their (rg2)lI2 values. Tkmethod1V2 was found to be useful for evaluating the microgel content in a sample, but not for (rg2)l12 values as calculated by Guinier's procedure nor those calculated by Zimm's procedure; the former were low and the latter were even incongruous. A comparative analysis of the theoretical function P1(8)-versus-sin2 (8/2) and experimental (Kc/R(e)),,o-versus-sin' (8/2) curvEdlowed to discuss the effect of the course of these curves at small angles from Oo to 30° on a, and (rg2)lI2 as determined for the high and low molecular weight polystyrene mixtures in toluene as solvent.

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“…There are many literature data for the refractive index of polymer solutions in the low polymer concentration range. 5 The solution refractive index can be described by the weighted summation of the refractive index of individual components in a system such as polystyrene (PS) and toluene. The spincoating process can be approximated as a n isothermal process6; therefore, the refractive indexes a t room temperature are used.…”

Section: Laser Interferometrymentioning

confidence: 99%

Solvent concentration measurement for spin coating

Bullwinkel

Campbell

1995

J of Applied Polymer Sci

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SYNOPSfSPlanarization of spin-coated polymer films is of great importance for the lithographic process in the microelectronic industry. Solvent retention is an important factor for determining the coating profile during spinning. In this research, solutions of polystyrene in toluene are spin-coated. The coating concentration during spinning is measured on-line using a laser interferometry technique. The optical measurement is evaluated by a n off-line gel permeation chromatograph technique. The experiments indicate that a smooth coating surface is required to use the optical method for concentration measurement. The optical technique also provides information regarding the coating surface structure during spinning. I NTRO D U CTl ONSpin coating is used in the microelectronic industry during the lithographic process to produce thin and uniform polymer films on silicon wafers. A puddle of the polymer solution is first deposited on a silicon wafer. The wafer is then accelerated to several thousand rotations per minute (rpm). The coating thickness decreases due to the simultaneous action of solution spin-off and solvent evaporation during spinning. The coating viscosity increases rapidly as the solvent evaporates until the coating becomes so viscous that spin-off stops and the film thins solely by solvent evaporation. Finally, a dry and uniform coating of about 1 micron thickness is left on the wafer. The process usually lasts for tens of seconds.Often, there is topography on the substrate. In this case, a planar coating surface is required on top of the uneven substrate. The concentration of solvent within the coating might play an important role in coating planarization. The coating profile during spinning is determined by the simultaneous action of centrifugal force, capillary force, viscous force, and solvent evaporation. Leveling of the coating surface is enhanced by the coating surface tension and surface curvature and is retarded by the ~~ ~

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Specific refractive index increments of polymer solutions. Part I. Literature values

Cited by 53 publications

References 224 publications

Dispersions or solutions? A mechanism for certain thickening agents

Dispersions or solutions? A mechanism for certain thickening agents

Light-scattering studies on solutions of high and low molecular weight polystyrene mixtures used as models of microgel-containing solutions

Solvent concentration measurement for spin coating

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