Abstract
The viscous behavior of polymers in nanometer scale volumes can significantly differ from bulk, due to the large free surfaces and the dominating molecular heterogeneity at nanoscale. In this study, we present the first experimental investigation on the creep and strain rate behavior of electrospun polyacrylonitrile (PAN) nanofibers. The apparatus used in this study was a MEMS-based platform, developed by the authors with the addition of a feedback loop to (a) maintain constant force on a nanofiber during a creep experiment and (b) vary the applied strain rate to investigate the viscoplastic response of amorphous polymer nanofibers. The creep compliance was found to be highly dependent on the nanofiber diameter, increasing with its diameter. In agreement with previous literature studies, it was concluded that the higher stiffness of thinner nanofibers was due to higher molecular alignment. A semi-empirical model was proposed to describe the experimentally determined viscous response of the PAN nanofibers, was composed of a Langevin spring and an Eyring’s dashpot to capture the strain rate sensitive yield stress and the orientation hardening observed in our experiments. The present experiments coupled with the semi-empirical model are among the first efforts to understand viscous phenomena at the nanoscale.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Preview
Unable to display preview. Download preview PDF.
References
Imai Y and Brown N, 1976 The effect of strain rate on craze yielding, shear yielding and brittle fracture of polymers at 77K Journal of Polymer Science, Polymer Physics Edition 14 723–39
Bauwens J C, Bauwens-Crowet C and Home`s G., 1969 Tensile yield-stress behavior of poly(vinyl chloride) and polycarbonate in the glass transition region. Journal of Polymer Science : Part A-2 7 1745–54
Dioh N N, Ivankovic A, Leevers P S and Williams J G, 1994 High strain rate behaviour of polymers Journal De Physique. IV : JP 4 C8-(119–124)
Bauwens J C, 1972 Relation between the compression yield stress and the mechanical loss peak of bisphenol-A-polycarbonate in the β transition range Journal of Materials Science 7 577–84
Findley W N, Lai J S and Onaran K, 1989 Creep and Relaxation of Nonlinear Viscoelastic Materials July Publisher: Dover Publications
Wu X F and Dzenis Y A, 2004 Size effect in polymer nanofibers under tension Journal of Applied Physics 102 044306
Dayal P and Kyu T, 2006 Porous fiber formation in polymer-solvent system undergoing solvent Evaporation Journal of Applied Physics 100 043512
Michler G H, Kausch H H and Adhikari R, 2006 Modeling of thin layer yielding in polymers Journal of Macromolecular Science: Physics 45 727–39
Haward R N, 2007 Strain hardening of high density polyethylene Journal of Polymer Science: Part B: Polymer Physics 45 1090–9
Haward R N, 1993 Strain hardening of thermoplastics Macromolecules 26 5860–9
Naraghi M, Chasiotis I, Dzenis Y et al. 2007 A novel method for the mechanical characterization of polymeric nanofibers Review of Scientific Instruments 78 085108–1 - 8
Naraghi M, Chasiotis I, Kahn H et al, 2007 Mechanical deformation and failure of electrospun polyacrylonitrile nanofibers as a function of strain rate. Applied Physics Letters 91 151901 1–3
K. Jonnalagadda, I. Chasiotis, J. Lambros, R. Polcawich, J. Pulskamp, and M. Dubey, “Experimental Investigation of Strain Rate Dependence in Nanocrystalline Pt Films,” Experimental Mechanics 50 (1)25-35, 2010
Shelby M D and Wilkes G L, 1998 The effect of molecular orientation on the Physical ageing of amorphous polymers - dilatometric and mechanical creep behaviour Polymer 39 6767–79
Haward R N and Thackray G, 1968 The use of a mathematical model to describe isothermal stress-strain curves in glassy thermoplastics Proceedings of the Royal Society of London Series A, Mathematical and Physical Sciences 302 453–72
Arruda E M and Boyce M C, 1993 Evolution of plastic anisotropy in amorphous polymers during finite straining International Journal of Plasticity 9 697–720
Haward R N, 2007 Strain hardening of high density polyethylene Journal of Polymer Science: Part B: Polymer Physics 45 1090–9
Haward R N, 1993 Strain hardening of thermoplastics Macromolecules 26 5860–9
Author information
Authors and Affiliations
Corresponding author
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2011 Springer Science+Business Media, LLC
About this paper
Cite this paper
Naraghi, M., Chasiotis, I. (2011). Viscoelastic and Viscoplastic Mechanical Behavior of Polymeric Nanofibers: An Experimental and Theoretical Approach. In: Proulx, T. (eds) Time Dependent Constitutive Behavior and Fracture/Failure Processes, Volume 3. Conference Proceedings of the Society for Experimental Mechanics Series. Springer, New York, NY. https://doi.org/10.1007/978-1-4419-9794-4_34
Download citation
DOI: https://doi.org/10.1007/978-1-4419-9794-4_34
Published:
Publisher Name: Springer, New York, NY
Print ISBN: 978-1-4419-9498-1
Online ISBN: 978-1-4419-9794-4
eBook Packages: EngineeringEngineering (R0)