Abstract
Recent models of the glass transition rationalize the relevant features of vitrification by introducing the concept of medium range order in supercooled liquids. In particular, a crucial role is assigned to the orientational order induced by intermolecular bonding (bond orientational order , BOO). Although this idea is very appealing, severe difficulties limit the experimental determination of the BOO in molecular liquids: because of the small difference in entropy and in form factor between the isotropic liquid and the phase rich in orientational order, calorimetry and scattering techniques cannot be used to assess the BOO. In this chapter we describe an innovative model to investigate BOO via broadband dielectric spectroscopy . We verified that ultrathin films of polyols deposited by physical vapor deposition below their glass transition temperature show an extraordinary enhancement in bond orientational, indicated by a huge enhancement of the dielectric strength with respect to the bulk values. Hint of an underlying phase transition was found from a liquid phase enriched in bond orientational order, with a metastable character, towards an ordinary liquid phase. The kinetic stability of the metastable phase could be tuned by varying the deposition conditions and the molecular size. The impact of film thickness and of the presence of a solid substrate on the persistence of enhanced BOO were also investigated. We demonstrate that confinement stabilizes the non-equilibrium character of our supercooled liquids with enhanced orientational order.
This is a preview of subscription content, log in via an institution to check access.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Abbreviations
- Δε maxN :
-
Maximum value of ΔεN
- g 3D6 :
-
Spatial correlation function of g6
- LFSs:
-
Locally favoured structures
- μ:
-
Dielectric dipole moment
- m:
-
Fragility index
- MROL:
-
Medium Range Order Liquid
- OL:
-
Ordinary Liquid
- S:
-
Concentration of locally favoured structures
- τ:
-
Structural relaxation time
- Tg :
-
Glass transition temperature
- TOP:
-
Two Order Parameters (Model)
- v:
-
MROL to OL transformation velocity
References
Capponi, S., Napolitano, S., Wübbenhorst, M.: Nat. Commun. 3, 1233 (2012)
Steinhardt, P.J., Nelson, D.R., Ronchetti, M.: Phys. Rev. B 28, 784 (1983)
Tanaka, H.: J. Chem. Physics 111, 3163 (1999)
Tanaka, H.: J. Phys. Condens. Matter 23, 17 (2011)
Shintani, H., Tanaka, H.: Nat. Phys. 2, 200 (2006)
Tanaka, H., Kawasaki, T., Shintani, H., Watanabe, K.: Nat. Mater. 9, 324 (2010)
Tarjus, G., Kivelson, S.A., Nussinov, Z., Viot, P.: J. Phys. Condens. Matter 17, R1143 (2005)
Hohenberg, P. C., Halperin, B. I.: Rev. Mod. Phys. 49, 435 (1977)
See supplementary information of Ref. [5] http://www.nature.com/nphys/journal/v2/n3/extref/nphys235-s1.pdf. Accessed 23 April 2015
The definition the definition of the hexatic order parameter in a 3D system, is given by \({\text{g}}_{ 6}^{{ 3 {\text{D}}}} \left( {\text{r}} \right){ = }\frac{{ 4\uppi}}{ 13}{{\left\langle {\sum\limits_{\text{m = - 6}}^{ 6} {{\text{Q}}_{{ 6 {\text{m}}}} \left( {\text{r}} \right){\text{Q*}}_{{ 6 {\text{m}}}} \left( 0\right)} } \right\rangle } \mathord{\left/ {\vphantom {{\left\langle {\sum\limits_{\text{m = - 6}}^{ 6} {{\text{Q}}_{{ 6 {\text{m}}}} \left( {\text{r}} \right){\text{Q*}}_{{ 6 {\text{m}}}} \left( 0\right)} } \right\rangle } {\text{g(r)}}}} \right. \kern-0pt} {\text{g(r)}}}\) where Q6m is the complex bond order parameter in 3D, g(r) is the normalized to the radial distribution. Numerical simulations reported in ref 8 proved that g 3D6 is well fitted by eq.7
Oh, S.H., Kauffmann, Y., Scheu, C., Kaplan, W.D., Rühle, M.: Science 310, 661 (2005)
Swallen, S.F., Kearns, K.L., Mapes, M.K., Kim, Y.S., McMahon, R.J., Ediger, M.D., Wu, T., Yu, L., Satija, S.: Science 315, 353 (2007)
Pauling, L.: The Nature of the Chemical Bond. Cornell University Press (1939)
Note: EOH•••O = 8-11 kBT/ bond, Douglas, B.E., McDaniel, D.H., Alexander, J.J.: Concepts and Models of Inorganic Chemistry. Wiley, New York City (1994)
The reader should note that, in case of centrosymmetric structures the term z<cosy>=0, and the Kirkwood factor is 1. In this case Δε provides no information about the average orientational order. However, that does not occur for our samples, because poliols ar linear chains and very unlikely they can form centrosymmetric structures via hydrogen intermolecular bondings
Capponi, S., Napolitano, S., Behrnd, N.R., Couderc, G., Hulliger, J., Wübbenhorst, M.: J. Phys. Chem. C 114, 16696 (2010)
Asai, M., Shibayama, M., Koike, Y.: Macromolecules 44, 6615 (2011)
Napolitano, S., Wübbenhorst, M.: Macromolecules 39, 5967 (2006)
Rotella, C., Wübbenhorst, M., Napolitano, S.: Soft Matter 7, 5260 (2011)
Paluch, M., Grzybowska, K., Grzybowski, A.: J. Phys. Condens. Matter 19, 12 (2007)
Watanabe, K., Kawasaki, T., Tanaka, H.: Nat. Mater. 10, 512 (2011)
Swallen, S.F., Traynor, K., McMahon, R.J., Ediger, M.D., Mates, T.E.: Phys. Rev. Lett. 102, 065503 (2009)
Author information
Authors and Affiliations
Corresponding authors
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2015 Springer International Publishing Switzerland
About this chapter
Cite this chapter
Capponi, S., Napolitano, S., Wübbenhorst, M. (2015). 1D Confinement Stabilizes Non-equilibrium Liquid Phase with Enhanced Orientational Order. In: Napolitano, S. (eds) Non-equilibrium Phenomena in Confined Soft Matter. Soft and Biological Matter. Springer, Cham. https://doi.org/10.1007/978-3-319-21948-6_10
Download citation
DOI: https://doi.org/10.1007/978-3-319-21948-6_10
Published:
Publisher Name: Springer, Cham
Print ISBN: 978-3-319-21947-9
Online ISBN: 978-3-319-21948-6
eBook Packages: Physics and AstronomyPhysics and Astronomy (R0)