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Size-dependent mechanical behavior of free-standing glassy polymer thin films

Published online by Cambridge University Press:  05 November 2014

Wenjie Xia  and
Sinan Keten
Wenjie Xia
Affiliation:
Department of Civil & Environmental Engineering, Northwestern University, Evanston, Illinois 60208-3109, USA
Sinan Keten*
Affiliation:
Department of Civil & Environmental Engineering, Northwestern University, Evanston, Illinois 60208-3109, USA
*
a) Address all correspondence to this author. e-mail: s-keten@northwestern.edu
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Abstract

The mechanical properties of nanoscale free-standing polymer thin films exhibit size dependence due to surface effects. However, it remains a challenge to determine the length scales at which differences are exhibited between film and bulk polymer properties. Here we use molecular dynamics simulations to uncover the dependence of elastic modulus (E) of free-standing films on film thickness and bulk properties. Comparison of the glass transition temperature (T g) and E indicates that T g converges to the bulk value slightly faster as the film thickness increases. The free-surface effects that give rise to a depression in E and T g are observed to be stronger for polymers with weaker intermolecular interactions. The most intriguing aspect of our study is the finding that despite the observed decrease in the modulus of the film up to a thickness of over 100 nm, the local stress distribution reveals that the preserved length scale of perturbation of the free surface is only several nanometers.

Keywords

elastic propertiesfilmpolymer
Type
Articles
Information
Journal of Materials Research , Volume 30 , Issue 1: Focus Issue: Soft Nanomaterials , 14 January 2015 , pp. 36 - 45
Copyright
Copyright © Materials Research Society 2015 

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References

REFERENCES

Ito, H.: Chemical amplification resists for microlithography. In Microlithography · Molecular Imprinting (Springer, Heidelberg, Germany, 2005), p. 37.Google Scholar
Ajayan, P.M., Schadler, L.S., and Braun, P.V.: Nanocomposite Science and Technology (Wiley, New York, USA, 2006).Google Scholar
Bertrand, P., Jonas, A., Laschewsky, A., and Legras, R.: Ultrathin polymer coatings by complexation of polyelectrolytes at interfaces: Suitable materials, structure and properties. Macromol. Rapid Commun. 21(7), 319 (2000).Google Scholar
Rowe, B.W., Freeman, B.D., and Paul, D.R.: Physical aging of ultrathin glassy polymer films tracked by gas permeability. Polymer 50(23), 5565 (2009).Google Scholar
Chen, J.R., Miao, Y.Q., He, N.Y., Wu, X.H., and Li, S.J.: Nanotechnology and biosensors. Biotechnol. Adv. 22(7), 505 (2004).Google Scholar
Yoshimoto, K., Stoykovich, M.P., Cao, H.B., de Pablo, J.J., Nealey, P.F., and Drugan, W.J.: A two-dimensional model of the deformation of photoresist structures using elastoplastic polymer properties. J. Appl. Phys. 96(4), 1857 (2004).Google Scholar
Sharma, A. and Reiter, G.: Instability of thin polymer films on coated substrates: Rupture, dewetting, and drop formation. J. Colloid Interface Sci. 178(2), 383 (1996).Google Scholar
Roth, C.B. and Dutcher, J.R.: Glass transition and chain mobility in thin polymer films. J. Electroanal. Chem. 584(1), 13 (2005).Google Scholar
Priestley, R.D., Ellison, C.J., Broadbelt, L.J., and Torkelson, J.M.: Structural relaxation of polymer glasses at surfaces, interfaces and in between. Science 309(5733), 456 (2005).Google Scholar
Forrest, J.A. and Mattsson, J.: Reductions of the glass transition temperature in thin polymer films: Probing the length scale of cooperative dynamics. Phys. Rev. E 61, R53 (2000).CrossRefGoogle ScholarPubMed
Torres, J.M., Stafford, C.M., and Vogt, B.D.: Elastic modulus of amorphous polymer thin films: Relationship to the glass transition temperature. ACS Nano 3(9), 2677 (2009).Google Scholar
Hanakata, P.Z., Douglas, J.F., and Starr, F.W.: Interfacial mobility scale determines the scale of collective motion and relaxation rate in polymer films. Nat. Commun. 5, 4163 (2014).CrossRefGoogle ScholarPubMed
Xia, W. and Keten, S.: Coupled effects of substrate adhesion and intermolecular forces on polymer thin film glass-transition behavior. Langmuir 29(41), 12730 (2013).Google Scholar
Hossain, D., Tschopp, M.A., Ward, D.K., Bouvard, J.L., Wang, P., and Horstemeyer, M.F.: Molecular dynamics simulations of deformation mechanisms of amorphous polyethylene. Polymer 51(25), 6071 (2010).CrossRefGoogle Scholar
Li, J., Mulder, T., Vorselaars, B., Lyulin, A.V., and Michels, M.A.J.: Monte Carlo simulation of uniaxial tension of an amorphous polyethylene-like polymer glass. Macromolecules 39(22), 7774 (2006).Google Scholar
Lyulin, A.V., Balabaev, N.K., Mazo, M.A., and Michels, M.A.J.: Molecular dynamics simulation of uniaxial deformation of glassy amorphous atactic polystyrene. Macromolecules 37(23), 8785 (2004).Google Scholar
Gray, L.A.G. and Roth, C.B.: Stability of polymer glasses vitrified under stress. Soft Matter 10(10), 1572 (2014).Google Scholar
Rottler, J.: Fracture in glassy polymers: a molecular modeling perspective. J. Phys.: Condens. Matter. 21(46), 463101 (2009).Google Scholar
Hudzinskyy, D., Michels, M.A.J., and Lyulin, A.V.: Mechanical properties and local mobility of atactic-polystyrene films under constant-shear deformation. J. Chem. Phys. 137(12), (2012).Google Scholar
Landel, R.F. and Nielsen, L.E.: Mechanical Properties of Polymers and Composites, 2nd ed. (CRC Press, New York, USA, 1993).CrossRefGoogle Scholar
Riggleman, R.A., Douglas, J.F., and de Pablo, J.J.: Antiplasticization and the elastic properties of glass-forming polymer liquids. Soft Matter 6(2), 292 (2010).Google Scholar
Kim, S., Mundra, M.K., Roth, C.B., and Torkelson, J.M.: Suppression of the Tg-nanoconfinement effect in thin poly(vinyl acetate) films by sorbed water. Macromolecules 43(11), 5158 (2010).Google Scholar
Torres, J.M., Stafford, C.M., and Vogt, B.D.: Manipulation of the elastic modulus of polymers at the nanoscale: Influence of UV−ozone cross-linking and plasticizer. ACS Nano 4(9), 5357 (2010).Google Scholar
Ellison, C.J., Mundra, M.K., and Torkelson, J.M.: Impacts of polystyrene molecular weight and modification to the repeat unit structure on the glass transition−nanoconfinement effect and the cooperativity length scale. Macromolecules 38(5), 1767 (2005).Google Scholar
Xia, W., Hsu, D.D., and Keten, S.: Dependence of polymer thin film adhesion energy on cohesive interactions between chains. Macromolecules 47(15), 5286 (2014).CrossRefGoogle Scholar
Grohens, Y., Brogly, M., Labbe, C., David, M-O., and Schultz, J.: Glass transition of stereoregular poly(methyl methacrylate) at interfaces. Langmuir 14(11), 2929 (1998).Google Scholar
Grohens, Y., Hamon, L., Reiter, G., Soldera, A., and Holl, Y.: Some relevant parameters affecting the glass transition of supported ultra-thin polymer films. Eur. Phys. J. E 8(2), 217 (2002).Google Scholar
Stafford, C.M., Vogt, B.D., Harrison, C., Julthongpiput, D., and Huang, R.: Elastic moduli of ultrathin amorphous polymer films. Macromolecules 39(15), 5095 (2006).Google Scholar
Delcambre, S.P., Riggleman, R.A., de Pablo, J.J., and Nealey, P.F.: Mechanical properties of antiplasticized polymer nanostructures. Soft Matter 6(11), 2475 (2010).CrossRefGoogle Scholar
O'Connell, P.A. and McKenna, G.B.: Dramatic stiffening of ultrathin polymer films in the rubbery regime. Eur. Phys. J. E 20(2), 143 (2006).Google Scholar
Wang, J. and McKenna, G.B.: Viscoelastic and glass transition properties of ultrathin polystyrene films by dewetting from liquid glycerol. Macromolecules 46(6), 2485 (2013).Google Scholar
O'Connell, P.A. and McKenna, G.B.: Rheological measurements of the thermoviscoelastic response of ultrathin polymer films. Science 307(5716), 1760 (2005).Google Scholar
Evans, C.M., Narayanan, S., Jiang, Z., and Torkelson, J.M.: Modulus, confinement, and temperature effects on surface capillary wave dynamics in bilayer polymer films near the glass transition. Phys. Rev. Lett. 109(3), 038302 (2012).CrossRefGoogle ScholarPubMed
Xia, W., Mishra, S., and Keten, S.: Substrate vs. free surface: Competing effects on the glass transition of polymer thin films. Polymer 54(21), 5942 (2013).Google Scholar
Hsu, D.D., Xia, W., Arturo, S.G., and Keten, S.: Systematic method for thermomechanically consistent coarse-graining: A universal model for methacrylate-based polymers. J. Chem. Theory Comput. 10(6), 2514 (2014).Google Scholar
Rosch, T.W., Brennan, J.K., Izvekov, S., and Andzelm, J.W.: Exploring the ability of a multiscale coarse-grained potential to describe the stress-strain response of glassy polystyrene. Phys. Rev. E 87(4), 042606 (2013).Google Scholar
Tsige, M. and Taylor, P.L.: Simulation study of the glass transition temperature in poly(methyl methacrylate). Phys. Rev. E 65(2), 021805 (2002).Google Scholar
Allen, M.P. and Tildesley, D.J.: Computer Simulation of Liquids (Oxford University Press, New York, USA, 1989).Google Scholar
Mulliken, A.D. and Boyce, M.C.: Mechanics of the rate-dependent elastic–plastic deformation of glassy polymers from low to high strain rates. Int. J. Solids Struct. 43(5), 1331 (2006).Google Scholar
Li, C. and Strachan, A.: Effect of thickness on the thermo-mechanical response of free-standing thermoset nanofilms from molecular dynamics. Macromolecules 44(23), 9448 (2011).Google Scholar
Huang, W.M., Yang, B., An, L., Li, C., and Chan, Y.S.: Water-driven programmable polyurethane shape memory polymer: Demonstration and mechanism. Appl. Phys. Lett. 86(11), (2005).Google Scholar
Sharp, J.S., Teichroeb, J.H., and Forrest, J.A.: The properties of free polymer surfaces and their influence on the glass transition temperature of thin polystyrene films. Eur. Phys. J. E 15(4), 473 (2004).Google Scholar
Sharp, J.S. and Forrest, J.A.: Free surfaces cause reductions in the glass transition temperature of thin polystyrene films. Phys. Rev. Lett. 91(23), 235701 (2003).Google Scholar
Mattsson, J., Forrest, J.A., and Borjesson, L.: Quantifying glass transition behavior in ultrathin free-standing polymer films. Phys. Rev. E 62(4), 5187 (2000).Google Scholar
Keddie, J.L., Jones, R.A.L., and Cory, R.A.: Size-dependent depression of the glass-transition temperature in polymer-films. Europhys. Lett. 27(1), 59 (1994).Google Scholar
Kim, J.H., Jang, J., and Zin, W-C.: Estimation of the thickness dependence of the glass transition temperature in various thin polymer films. Langmuir 16(9), 4064 (2000).Google Scholar
Forrest, J.A., Dalnoki-Veress, K., and Dutcher, J.R.: Brillouin light scattering studies of the mechanical properties of thin freely standing polystyrene films. Phys. Rev. E 58(5), 6109 (1998).CrossRefGoogle Scholar
Bodiguel, H. and Fretigny, C.: Reduced viscosity in thin polymer films. Phys. Rev. Lett. 97(26), 266105 (2006).Google Scholar
Hutcheson, S.A. and McKenna, G.B.: Nanosphere embedding into polymer surfaces: A viscoelastic contact mechanics analysis. Phys. Rev. Lett. 94(7), 076103 (2005).Google Scholar
Merabia, S., Sotta, P., and Long, D.R.: A microscopic model for the reinforcement and the nonlinear behavior of filled elastomers and thermoplastic elastomers (Payne and Mullins effects). Macromolecules 41(21), 8252 (2008).Google Scholar
Long, D. and Sotta, P.: Nonlinear and plastic behavior of soft thermoplastic and filled elastomers studied by dissipative particle dynamics. Macromolecules 39(18), 6282 (2006).Google Scholar
Papon, A., Merabia, S., Guy, L., Lequeux, F., Montes, H., Sotta, P., and Long, D.R.: Unique nonlinear behavior of nano-filled elastomers: From the onset of strain softening to large amplitude shear deformations. Macromolecules 45(6), 2891 (2012).Google Scholar
Watcharotone, S., Wood, C.D., Friedrich, R., Chen, X., Qiao, R., Putz, K., and Brinson, L.C.: Interfacial and substrate effects on local elastic properties of polymers using coupled experiments and modeling of nanoindentation. Adv. Eng. Mater. 13(5), 400 (2011).Google Scholar
Yoshimoto, K., Jain, T.S., Nealey, P.F., and de Pablo, J.J.: Local dynamic mechanical properties in model free-standing polymer thin films. J. Chem. Phys. 122(14), 144712 (2005).Google Scholar