Related Experiment Videos
Rigidity transition in polymer melts with van der Waals interaction.
Matthew L Wallace1, Béla Joós, Michael Plischke
1Ottawa-Carleton Institute for Physics, University of Ottawa Campus, Ottawa, Ontario, Canada K1N 6N5.
Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics
|December 17, 2004
Summary
Polymeric glasses exhibit rigid behavior below a specific temperature (T1), which is lower than the glass transition temperature (TG). This study investigates rigidity onset and shear effects in polymer melts.
Area of Science:
- Materials Science
- Polymer Physics
- Computational Chemistry
Background:
- The glass transition (GT) in polymers is a critical phenomenon affecting material properties.
- Understanding rigidity onset is crucial for designing stable polymeric materials.
Purpose of the Study:
- To investigate the onset of rigidity in short-chain polymer melts near the glass transition.
- To analyze the effects of external shear on the system's local and global properties.
Main Methods:
- Utilized a bead-spring model with Lennard-Jones potentials for polymer melt simulation.
- Employed isothermal compression to achieve equilibrium configurations, minimizing cooling-rate effects.
- Monitored heat capacity (CP), diffusion constants (D), viscosity (eta), and shear modulus (Gt and mu).
Main Results:
- Polymeric glasses demonstrate long-time rigid behavior exclusively below a characteristic temperature T1 (T1 < TG).
- Detailed analysis of local and global system responses to applied shear was performed.
- Linear and nonlinear relaxation regimes under shear were characterized.
Conclusions:
- Rigidity in polymer melts is strongly dependent on temperature relative to the glass transition.
- External shear significantly influences the relaxation dynamics and structural properties of polymeric glasses.