Nonlinear Oscillatory Shear Mechanical Responses
Mechanical dynamic oscillatory shear test is generally used to characterize and investigate mechanical properties of complex fluids or soft matters. Especially, small amplitude oscillatory shear (SAOS) tests are the canonical method for probing the linear viscoelastic properties of complex fluids because of the firm theoretical background and the ease of implementing suitable test protocols. Material functions of SAOS tests are analogous with dielectric functions from dielectric spectroscopy. However, recently nonlinear responses under large amplitude oscillatory shear (LAOS) flows are also under the spotlight due to usefulness to characterize complex fluids. In this chapter, LAOS tests are reviewed. The key to successful LAOS test is the analysis and fundamental understanding of the nonlinear mechanical responses. To analyze nonlinear responses, there are several analyzing methods and various nonlinear material functions suggested by several researchers. Among the several methods available, FT (Fourier transform)-rheology is intensively reviewed. Finally, several applications to investigate complex fluids (polymer melt and solution, polymer composite and blend, emulsion and block copolymer, and so on) are introduced.
KeywordsSAOS LAOS FT-rheology
The KH acknowledge the financial support of the Alexander von Humboldt Foundation. The authors thank Valerian Hirschberg, Miriam Cziep, and Hyeong Yong Song for supplying figures and Carlo Botha for English proofreading.
Substantial parts (especially Sect. 3 and 4) of this chapter are taken from a rheological review  where rheological nonlinearities are explained in more detail but might not be read by scientists with a background in dielectric spectroscopy. Consequently, this chapter will be very helpful for the reader with a dielectric background to envision the similar concepts of both methodologies.
- 1.R.G. Larson, The structure and rheology of complex fluids (Oxford University Press, New York, 1999)Google Scholar
- 2.F.A. Morrison, Understanding Rheology (Oxford University Press, New York, 2001)Google Scholar
- 4.J.D. Ferry, Viscoelastic Properties of Polymers (Wiley, NY, 1980)Google Scholar
- 5.R.B. Bird, R.C. Armstrong, O. Hassager, Dynamics of polymeric Liquids, vol. 1 (Wiley, NY, 1987)Google Scholar
- 7.J.M. Dealy, K.F. Wissbrun, Melt rheology and its role in plastics processing: theory and applications (VNR, NY, 1990)Google Scholar
- 9.Dealy J.M., Larson R.G. Structure and rheology of molten polymers (2006)Google Scholar
- 11.A.J. Giacomin, J.M. Dealy, Large-amplitude oscillatory shear, in Techniques in Rheological Measurements, Chapter 4, ed. by A.A. Collyer (Chapman and Hall, London, 1993)Google Scholar
- 16.K. Hyun, J.G. Nam, M. Wilhelm, K.H. Ahn, S.J. Lee, Nonlinear response of complex fluids under LAOS (large amplitude oscillatory shear) flow. Korea-Australia Rheology J 15, 97–105 (2003)Google Scholar
- 43.D. Merger, M. Abbasi, J. Merger, A.J. Giacomin, Ch. Saengow, M. Wilhelm, Simple scalar model for large amplitude oscillatory shear. Appl. Rheol. 26, 53809 (2016)Google Scholar
- 47.J.L. Leblanc, Non-linear viscoelastic characterization of natural rubber gum through large amplitude harmonic experiments. J. Rubber. Res. 10, 63–88 (2007)Google Scholar
- 50.I. Vittorias, M. Parkinson, K. Klimke, B. Debbaut, M. Wilhelm, Detection and quantification of industrial polyethylene branching topologies via Fourier-transform rheology. NMR and simulation using the Pom-pom model Rheol. Acta 46, 321–340 (2007)Google Scholar