Dynamic Monte Carlo Simulations of Strain-Induced Crystallization in Multiblock Copolymers: Effects of Asymmetric...

Area of Science:

• Materials Science
• Polymer Science
• Computational Materials Science

Background:

• Thermoplastic elastomers (TPEs) like polyurethanes and olefin block copolymers rely on stretching for elasticity and toughness.
• The size diversity of hard block semicrystalline microdomains is crucial for TPE properties.
• Previous studies explored strain-induced crystallization in block copolymers, noting dilution effects.

Purpose of the Study:

• To investigate the impact of asymmetric block rigidity on strain-induced crystallization in diblock copolymers.
• To understand how thermodynamic and kinetic rigidity differences influence semicrystalline microdomain size diversity.

Main Methods:

• Dynamic Monte Carlo simulations were employed to model strain-induced crystallization.
• The study focused on diblock copolymers with alternating crystallizable and noncrystallizable blocks.
• Simulations analyzed the effects of varying thermodynamic and kinetic rigidity between blocks.

Main Results:

• When crystallizable blocks possess higher thermodynamic rigidity, large semicrystalline domains grow larger, and small domains increase in number, enhancing size diversity.
• Asymmetric kinetic rigidity between blocks showed minimal impact on domain size diversity.
• Dilution effects on domain size diversity were observed to persist from diblock to tetrablock copolymers.

Conclusions:

• Enhancing the thermodynamic rigidity of crystallizable blocks relative to noncrystallizable blocks can improve the toughness of semicrystalline thermoplastic elastomers through industrial stretching.
• The findings provide insights into the structure-property relationships in thermoplastic elastomers.
• This research offers a pathway for optimizing TPE processing for superior material performance.