Skip to main content
SpringerLink
Log in

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

  • Articles
  • Published:
Journal of Materials Research Aims and scope Submit manuscript

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 (Tg) and E indicates that Tg 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 Tg 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.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

FIG. 1
FIG. 2
FIG. 3
FIG. 4
FIG. 5
FIG. 6

Similar content being viewed by others

References

  1. H. Ito: Chemical amplification resists for microlithography. In Microlithography · Molecular Imprinting (Springer, Heidelberg, Germany, 2005), p. 37.

    Chapter  Google Scholar 

  2. P.M. Ajayan, L.S. Schadler, and P.V. Braun: Nanocomposite Science and Technology (Wiley, New York, USA, 2006).

    Google Scholar 

  3. P. Bertrand, A. Jonas, A. Laschewsky, and R. Legras: Ultrathin polymer coatings by complexation of polyelectrolytes at interfaces: Suitable materials, structure and properties. Macromol. Rapid Commun. 21(7), 319 (2000).

    Article  CAS  Google Scholar 

  4. B.W. Rowe, B.D. Freeman, and D.R. Paul: Physical aging of ultrathin glassy polymer films tracked by gas permeability. Polymer 50(23), 5565 (2009).

    Article  CAS  Google Scholar 

  5. J.R. Chen, Y.Q. Miao, N.Y. He, X.H. Wu, and S.J. Li: Nanotechnology and biosensors. Biotechnol. Adv. 22(7), 505 (2004).

    Article  CAS  Google Scholar 

  6. K. Yoshimoto, M.P. Stoykovich, H.B. Cao, J.J. de Pablo, P.F. Nealey, and W.J. Drugan: A two-dimensional model of the deformation of photoresist structures using elastoplastic polymer properties. J. Appl. Phys. 96(4), 1857 (2004).

    Article  CAS  Google Scholar 

  7. A. Sharma and G. Reiter: Instability of thin polymer films on coated substrates: Rupture, dewetting, and drop formation. J. Colloid Interface Sci. 178(2), 383 (1996).

    Article  CAS  Google Scholar 

  8. C.B. Roth and J.R. Dutcher: Glass transition and chain mobility in thin polymer films. J. Electroanal. Chem. 584(1), 13 (2005).

    Article  CAS  Google Scholar 

  9. R.D. Priestley, C.J. Ellison, L.J. Broadbelt, and J.M. Torkelson: Structural relaxation of polymer glasses at surfaces, interfaces and in between. Science 309(5733), 456 (2005).

    Article  CAS  Google Scholar 

  10. J.A. Forrest and J. Mattsson: Reductions of the glass transition temperature in thin polymer films: Probing the length scale of cooperative dynamics. Phys. Rev. E 61, R53 (2000).

    Article  CAS  Google Scholar 

  11. J.M. Torres, C.M. Stafford, and B.D. Vogt: Elastic modulus of amorphous polymer thin films: Relationship to the glass transition temperature. ACS Nano 3(9), 2677 (2009).

    Article  CAS  Google Scholar 

  12. P.Z. Hanakata, J.F. Douglas, and F.W. Starr: Interfacial mobility scale determines the scale of collective motion and relaxation rate in polymer films. Nat. Commun. 5, 4163 (2014).

    Article  CAS  Google Scholar 

  13. W. Xia and S. Keten: Coupled effects of substrate adhesion and intermolecular forces on polymer thin film glass-transition behavior. Langmuir 29(41), 12730 (2013).

    Article  CAS  Google Scholar 

  14. D. Hossain, M.A. Tschopp, D.K. Ward, J.L. Bouvard, P. Wang, and M.F. Horstemeyer: Molecular dynamics simulations of deformation mechanisms of amorphous polyethylene. Polymer 51(25), 6071 (2010).

    Article  CAS  Google Scholar 

  15. J. Li, T. Mulder, B. Vorselaars, A.V. Lyulin, and M.A.J. Michels: Monte Carlo simulation of uniaxial tension of an amorphous polyethylene-like polymer glass. Macromolecules 39(22), 7774 (2006).

    Article  CAS  Google Scholar 

  16. A.V. Lyulin, N.K. Balabaev, M.A. Mazo, and M.A.J. Michels: Molecular dynamics simulation of uniaxial deformation of glassy amorphous atactic polystyrene. Macromolecules 37(23), 8785 (2004).

    Article  CAS  Google Scholar 

  17. L.A.G. Gray and C.B. Roth: Stability of polymer glasses vitrified under stress. Soft Matter 10(10), 1572 (2014).

    Article  CAS  Google Scholar 

  18. J. Rottler: Fracture in glassy polymers: a molecular modeling perspective. J. Phys.: Condens. Matter. 21(46), 463101 (2009).

    Google Scholar 

  19. D. Hudzinskyy, M.A.J. Michels, and A.V. Lyulin: Mechanical properties and local mobility of atactic-polystyrene films under constant-shear deformation. J. Chem. Phys. 137(12), (2012).

  20. R.F. Landel and L.E. Nielsen: Mechanical Properties of Polymers and Composites, 2nd ed. (CRC Press, New York, USA, 1993).

    Book  Google Scholar 

  21. R.A. Riggleman, J.F. Douglas, and J.J. de Pablo: Antiplasticization and the elastic properties of glass-forming polymer liquids. Soft Matter 6(2), 292 (2010).

    Article  CAS  Google Scholar 

  22. S. Kim, M.K. Mundra, C.B. Roth, and J.M. Torkelson: Suppression of the Tg-nanoconfinement effect in thin poly(vinyl acetate) films by sorbed water. Macromolecules 43(11), 5158 (2010).

    Article  CAS  Google Scholar 

  23. J.M. Torres, C.M. Stafford, and B.D. Vogt: Manipulation of the elastic modulus of polymers at the nanoscale: Influence of UV−ozone cross-linking and plasticizer. ACS Nano 4(9), 5357 (2010).

    Article  CAS  Google Scholar 

  24. C.J. Ellison, M.K. Mundra, and J.M. Torkelson: 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).

    Article  CAS  Google Scholar 

  25. W. Xia, D.D. Hsu, and S. Keten: Dependence of polymer thin film adhesion energy on cohesive interactions between chains. Macromolecules 47(15), 5286 (2014).

    Article  CAS  Google Scholar 

  26. Y. Grohens, M. Brogly, C. Labbe, M-O. David, and J. Schultz: Glass transition of stereoregular poly(methyl methacrylate) at interfaces. Langmuir 14(11), 2929 (1998).

    Article  CAS  Google Scholar 

  27. Y. Grohens, L. Hamon, G. Reiter, A. Soldera, and Y. Holl: Some relevant parameters affecting the glass transition of supported ultra-thin polymer films. Eur. Phys. J. E 8(2), 217 (2002).

    Article  CAS  Google Scholar 

  28. C.M. Stafford, B.D. Vogt, C. Harrison, D. Julthongpiput, and R. Huang: Elastic moduli of ultrathin amorphous polymer films. Macromolecules 39(15), 5095 (2006).

    Article  CAS  Google Scholar 

  29. S.P. Delcambre, R.A. Riggleman, J.J. de Pablo, and P.F. Nealey: Mechanical properties of antiplasticized polymer nanostructures. Soft Matter 6(11), 2475 (2010).

    Article  CAS  Google Scholar 

  30. P.A. O’Connell and G.B. McKenna: Dramatic stiffening of ultrathin polymer films in the rubbery regime. Eur. Phys. J. E 20(2), 143 (2006).

    Article  CAS  Google Scholar 

  31. J. Wang and G.B. McKenna: Viscoelastic and glass transition properties of ultrathin polystyrene films by dewetting from liquid glycerol. Macromolecules 46(6), 2485 (2013).

    Article  CAS  Google Scholar 

  32. P.A. O’Connell and G.B. McKenna: Rheological measurements of the thermoviscoelastic response of ultrathin polymer films. Science 307(5716), 1760 (2005).

    Article  CAS  Google Scholar 

  33. C.M. Evans, S. Narayanan, Z. Jiang, and J.M. Torkelson: 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).

    Article  CAS  Google Scholar 

  34. W. Xia, S. Mishra, and S. Keten: Substrate vs. free surface: Competing effects on the glass transition of polymer thin films. Polymer 54(21), 5942 (2013).

    Article  CAS  Google Scholar 

  35. D.D. Hsu, W. Xia, S.G. Arturo, and S. Keten: Systematic method for thermomechanically consistent coarse-graining: A universal model for methacrylate-based polymers. J. Chem. Theory Comput. 10(6), 2514 (2014).

    Article  CAS  Google Scholar 

  36. T.W. Rosch, J.K. Brennan, S. Izvekov, and J.W. Andzelm: 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).

    Article  CAS  Google Scholar 

  37. M. Tsige and P.L. Taylor: Simulation study of the glass transition temperature in poly(methyl methacrylate). Phys. Rev. E 65(2), 021805 (2002).

    Article  CAS  Google Scholar 

  38. M.P. Allen and D.J. Tildesley: Computer Simulation of Liquids (Oxford University Press, New York, USA, 1989).

    Google Scholar 

  39. A.D. Mulliken and M.C. Boyce: 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).

    Article  CAS  Google Scholar 

  40. C. Li and A. Strachan: Effect of thickness on the thermo-mechanical response of free-standing thermoset nanofilms from molecular dynamics. Macromolecules 44(23), 9448 (2011).

    Article  CAS  Google Scholar 

  41. W.M. Huang, B. Yang, L. An, C. Li, and Y.S. Chan: Water-driven programmable polyurethane shape memory polymer: Demonstration and mechanism. Appl. Phys. Lett. 86(11), (2005).

  42. J.S. Sharp, J.H. Teichroeb, and J.A. Forrest: 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).

    Article  CAS  Google Scholar 

  43. J.S. Sharp and J.A. Forrest: Free surfaces cause reductions in the glass transition temperature of thin polystyrene films. Phys. Rev. Lett. 91(23), 235701 (2003).

    Article  CAS  Google Scholar 

  44. J. Mattsson, J.A. Forrest, and L. Borjesson: Quantifying glass transition behavior in ultrathin free-standing polymer films. Phys. Rev. E 62(4), 5187 (2000).

    Article  CAS  Google Scholar 

  45. J.L. Keddie, R.A.L. Jones, and R.A. Cory: Size-dependent depression of the glass-transition temperature in polymer-films. Europhys. Lett. 27(1), 59 (1994).

    Article  CAS  Google Scholar 

  46. J.H. Kim, J. Jang, and W-C. Zin: Estimation of the thickness dependence of the glass transition temperature in various thin polymer films. Langmuir 16(9), 4064 (2000).

    Article  CAS  Google Scholar 

  47. J.A. Forrest, K. Dalnoki-Veress, and J.R. Dutcher: Brillouin light scattering studies of the mechanical properties of thin freely standing polystyrene films. Phys. Rev. E 58(5), 6109 (1998).

    Article  CAS  Google Scholar 

  48. H. Bodiguel and C. Fretigny: Reduced viscosity in thin polymer films. Phys. Rev. Lett. 97(26), 266105 (2006).

    Article  CAS  Google Scholar 

  49. S.A. Hutcheson and G.B. McKenna: Nanosphere embedding into polymer surfaces: A viscoelastic contact mechanics analysis. Phys. Rev. Lett. 94(7), 076103 (2005).

    Article  CAS  Google Scholar 

  50. S. Merabia, P. Sotta, and D.R. Long: 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).

    Article  CAS  Google Scholar 

  51. D. Long and P. Sotta: Nonlinear and plastic behavior of soft thermoplastic and filled elastomers studied by dissipative particle dynamics. Macromolecules 39(18), 6282 (2006).

    Article  CAS  Google Scholar 

  52. A. Papon, S. Merabia, L. Guy, F. Lequeux, H. Montes, P. Sotta, and D.R. Long: Unique nonlinear behavior of nano-filled elastomers: From the onset of strain softening to large amplitude shear deformations. Macromolecules 45(6), 2891 (2012).

    Article  CAS  Google Scholar 

  53. S. Watcharotone, C.D. Wood, R. Friedrich, X. Chen, R. Qiao, K. Putz, and L.C. Brinson: Interfacial and substrate effects on local elastic properties of polymers using coupled experiments and modeling of nanoindentation. Adv. Eng. Mater. 13(5), 400 (2011).

    Article  CAS  Google Scholar 

  54. K. Yoshimoto, T.S. Jain, P.F. Nealey, and J.J. de Pablo: Local dynamic mechanical properties in model free-standing polymer thin films. J. Chem. Phys. 122(14), 144712 (2005).

    Article  CAS  Google Scholar 

Download references

ACKNOWLEDGMENTS

The authors acknowledge funding by the Army Research Office (award #W911NF-13-1-0241) and Department of Civil & Environmental Engineering and Department of Mechanical Engineering at Northwestern University. A supercomputing grant from Quest HPC System at Northwestern University is acknowledged.

Author information

Authors and Affiliations

  1. Department of Civil & Environmental Engineering, Northwestern University, Evanston, Illinois, 60208-3109, USA

    Wenjie Xia & Sinan Keten

Authors
  1. Wenjie Xia
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Sinan Keten
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Sinan Keten.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Xia, W., Keten, S. Size-dependent mechanical behavior of free-standing glassy polymer thin films. Journal of Materials Research 30, 36–45 (2015). https://doi.org/10.1557/jmr.2014.289

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1557/jmr.2014.289

Search

Navigation