Rheo-optics

Siesler, H. W. Rheo-Optical Fourier-TranformInfrared Spectroscopy Vibrational Spectra and Mechanical Properties of Polymers. Vol. 65, pp. 1 —78. 

An interesting feature of polarized IR spectroscopy is that rapid measurements can be performed while preserving molecular information (in contrast with birefringence) and without the need for a synchrotron source (X-ray diffraction). Time-resolved IRLD studies are almost exclusively realized in transmission because of its compatibility with various types of tensile testing devices. In the simplest implementation, p- and s-polarized spectra are sequentially acquired while the sample is deformed and/or relaxing. The time resolution is generally limited to several seconds per spectrum by the acquisition time of two spectra and by the speed at which the polarizer can be rotated. Siesler et al. have used such a rheo-optical technique to study the dynamics of multiple polymers and copolymers [40]. 

Since the tack and green strength of these rubbers may depend on their ability to undergo strain induced crystallization, this behavior was studied and compared with that shown by NR. Information on the strain induced crystallization behavior of these experimental rubbers was obtained from x-ray diffraction measurements and from rheo-optical studies. 

Rheo-optical Studies. One of the most useful techniques for studying the crystallization behavior of stereoregular polymers is rheo-optical measurements (11). 

Rheo-Optical Observations. The rheo-optical observations were made with a WILD stereoscope equipped with a custom made rotary optical stage using polarized light. The rotary optical stage described in detail elsewhere (9) was used for both the steady state shear and dynamic test conditions. 

Rheo-optical and rheological strudies of concentrated solutions of UHMWPE/paraffin oil (2-5% w/w concentration) systems indicate that these are pseudo-gels unlike the covalent bonded molecular networks which exhibit a true gel behavior. The viscoelastic properties of the UHMWPE/paraffin oil pseudo-gels,... 

We have omitted discussing such interesting properties of liquid-crystal solutions as the Frank elastic constants, the Leslie viscosity coefficients, cholesteric pitch, textured structure (or defects), and rheo-optics. Some of them are reviewed in recent literature [8,167], but the level of their experimental and theoretical studies still remains largely qualitative. 

Van Puyvelde, P., Antonov, Y.A., Moldenaers, P. (2002). Rheo-optical measurement of the interfacial tension of aqueous biopolymer mixtures. Food Hydrocolloids, 16, 395-402. 

Siesler, H. W. Polymer Deformation A Rheo-Optical Study by Fourier Transform Infrared Spectroscopy, preprint... 

K. Sondergaard and J. Lyngaae-Horgensen, eds., Rheo-physics of multiphase polymer systems characterization by rheo-optical techniques, Technomic Publ. Co., Lancaster, PA (1994). 

P. L. Frattini and G. G. Fuller, A note on phase-modulated flow birefringence a promising rheo-optical method, J. Rheol., 28 61, (1984). 

A.W. Chow, and G.G. Fuller, The rheo-optical response of rod-like chains subject to transient shear flow. Part I Model calculations on the effects of polydispersity, Macromolecules 18, 786 (1985) A.W. Chow, G.G. Fuller, D.G. Wallace and J.A. Madri, The rheo-optical response of rod-like chains subject to transient shear flow. Part II. Two-color flow birefringence measurements, Macromolecules 18,793 (1985) A.W. Chow, G.G. Fuller, D.G. Wallace and J.A. Madri, The rheo-optical response of rod-like shortened collagen protein to transient shear flow, Macromolecules, 18, 805 (1985). 

P. Navard, Rheo-optical and rheo-X-ray investigations of liquid crystalline polymers, in refenence 18. 

T. Asada, H. Muramatsu, R. Watanabe, and S. Onogi, Rheo-optical studies of racemic poly (y -benzyl glutamate) liquid crystals, Macromolecules, 13,867... 

M. M. Fromjmovic, A. Okagawa, and S. G. Mason, Rheo-optical transients in erythrocyte suspensions, Biochem. andBiophys. Research Comm., 62, 17 (1975). 

The mechanical and rheo-optical properties of Kraton 101 have been studied by Stein136) using films cast from methylethyl ketone and from toluene solutions. The stress-strain curves, birefringence-strain curve, stress relaxation, birefringence relaxation, and dynamic mechanical spectra are dependent upon the morphology of the copolymer which in turn is dependent upon the conditions of preparations of the samples. 

Onogi S and Asada T, "Rheo-Optics of Polymer Liquid Crystals", in "Rheology" (see Gen Ref Astarita, Marrucci ans Nicolai, Eds) Vol 1, pp 127-147. 

The initial cholesteric structure present, especially m dioxane, is considered to be separated into small fragments upon putting the solution between the cone and the plate of the rheogoniometer, and it appears unthinkable that the continuous cholesteric structure is kept during the rotation of the plate. Rheo-optical studies on the liquid crystalline solution have just started (52), and will supply extra information about the solution structure under shearing stresses. 

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