Optical Effects in Flow

Peterlin, A.

doi:10.1146/annurev.fl.08.010176.000343

Cited by 36 publications

(20 citation statements)

References 47 publications

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“…The presence of thermal gradients and solidification processes, however, somewhat complicates interpretation of the observed stress-optical behavior. One still tends to share the conclusion of Peterlin (29), that few reliable data for birefringence in extensional flow are available, which provides rauch of the motivation of the work on polymer solutions to be described here.…”

Section: Introductionmentioning

confidence: 89%

Streaming birefringence in extensional flow of polymer solutions

Talbott

Goddard

1979

Rheol Acta

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Section: Introductionmentioning

confidence: 89%

Streaming birefringence in extensional flow of polymer solutions

Talbott

Goddard

1979

Rheol Acta

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“…A reliable optical mapping of the stress distribution by flowinduced birefringence requires a 2D flow field, as no variations of the optical properties along the optical path are expected [14]. In reality however, such a requirement is never fulfilled: the flow is actually confined by viewing windows which bring about end effects.…”

Section: End Effects In Flow-induced Birefringence Experimentsmentioning

confidence: 99%

Lubricated optical rheometer for the study of two-dimensional complex flows of polymer melts

Soulages

Schweizer

Venerus

et al. 2008

Journal of Non-Newtonian Fluid Mechanics

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“…This should be a good approximation for concentrated systems. 17 With eq. (8), the birefringence can be calculated for all four models that are listed in Table I.…”

Section: Z)mentioning

confidence: 99%

“…By use of eqs. (17) and (18), the relation between the angular velocity of the rollers and the local velocity gradient at the stagnation point can be determined by measuring the transit times of particles in the flow. This was done for the glycerol system for several values of the parameter A.…”

Section: + -C I R C L E _ _ _ _ _ H Y P E R B O L a Netmentioning

confidence: 99%

Flow birefringence of concentrated polymer solutions in two‐dimensional flows

Fuller

Leal

1981

J. Polym. Sci. Polym. Phys. Ed.

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The results of flow birefringence measurements are reported for polymer solutions of moderate concentration subjected to a wide range of two‐dimensional flows. These flows were generated in a four‐roll mill which enables one to systematically vary the ratio of the vorticity to the rate of strain in the flow while holding the velocity gradient constant. It is shown that steady‐state birefringence data collected over a wide range of flow types can be correlated against the eigenvalue of the velocity gradient tensor, in agreement with criterion for strong and weak flows from model calculations. Transient birefringence measurements in which purely extensional flows were started from rest are also reported. It was observed that the birefringence went through a pronounced overshoot in time for two different polymer/solvent systems. Flow induced increases in the solution turbidity were also observed and the increased turbidity remained constant over a period of many hours after extensional flows were arrested. The birefringence, on the other hand, decayed to zero almost immediately after the flows were stopped. These changes in the turbidity suggest that crystallization of the polymer was occurring. The qualitative results of experiments are compared to recent network model calculations using the theory of Yamamoto for concentrated polymer systems. It is found that this model can predict qualitatively many of the experimental observations if the function describing the breakage of polymer chain entanglements is allowed to depend on the conformation of the polymer segments bridging the entanglements. In particular, this dependency of the entanglement breakage on the conformation of the network segments leads to a predicted overshoot of birefringence when purely extensional flows are started from rest. It is also demonstrated through this model that birefringence data taken over a wide range of flow types can be used to estimate the degree to which the network deforms affinely with the flow field.

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Optical Effects in Flow

Cited by 36 publications

References 47 publications

Streaming birefringence in extensional flow of polymer solutions

Streaming birefringence in extensional flow of polymer solutions

Lubricated optical rheometer for the study of two-dimensional complex flows of polymer melts

Flow birefringence of concentrated polymer solutions in two‐dimensional flows

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