Paper Number
PO98 

Session
Poster Session

Title
Testing the paradigm of an ideal glass transition by measuring viscoelastic properties of ultrastable polymeric glass

Presentation Date and Time
October 17, 2018 (Wednesday) 6:30

Track / Room
Poster Session / Woodway II/III

Authors (Click on name to view author profile)

1. McKenna, Gregory B. (Texas Tech University, Department of Chemical Engineering)
2. Yoon, Heedong (Texas Tech University, Chemical Engineering)

Author and Affiliation Lines (in printed abstract book)
Gregory B. McKenna and Heedong Yoon
Department of Chemical Engineering, Texas Tech University, Lubbock, TX 79409

Speaker / Presenter 
McKenna, Gregory B.

Text of Abstract
The dynamic behavior of glass forming liquids remains one of the greatest challenging problems in condensed matter physics. [1, 2] One important question is whether the equilibrium dynamic response deep in the glassy state follows super-Arrhenius behavior. [2] However, accessing the equilibrium dynamics deep in the glassy state requires geological aging times for the measurements, hence it is virtually impossible to investigate the equilibrium dynamics by simply aging sample for millions of years. [3] Recently, we have developed a vapor deposition approach to create ultrastable amorphous Teflon films [4] having a 57 K fictive temperature (Tf) reduction relative to the glass transition temperature (Tg). This large Tf reduction is close to the Kauzmann temperature, and gives an opportunity to study the dynamic behavior deep in the glassy regime. Here, we use this ultra-stable glass to study the relaxation behavior of the polymer in the temperature range between Tf and Tg where the glass has longer relaxation time than the equilibrium system. The relaxation behavior of stable Teflon films was measured using the TTU nano bubble inflation technique [5] by following Struik’s protocol [6]. We found that there is a strong deviation from VFT dynamics in the upper bound regime suggesting that the ideal glass transition may not exist.

[1] Anderson, P. W. Science 1995, 267, 1615.
[2] McKenna, G. B.; Simon, S. L. Macromolecules 2017, 50, (17), 6333-6361.
[3] Zhao, J.; Simon, S. L.; McKenna, G. B. Nat. Commun. 2013, 4, 1783.
[4] Yoon, H.; Koh, Y.P.; Simon, S.L.; McKenna, G. B. Macromolecules, 2017, 50, 4562-4574.
[5] O'Connell, P. A.; McKenna, G. B. Rev. Sci. Instrum. 2007, 78, 013901-1-013901-12.
[6] Struik, L. C. E. Physical Aging in Amorphous Polymers and Other Materials; Elsevier: Amsterdam, 1978.