Characteristic System Time Scales Can Influence the Collective Sequence Development of Nematically Ordered Copolymers

Area of Science:

• Polymer Chemistry
• Materials Science
• Chemical Engineering

Background:

• Copolymer sequence critically influences material properties, posing a significant control challenge.
• Previous work demonstrated emergent nematic alignment in stiff polymers during step-growth polymerization.
• Alignment extent and timing impact polymerization kinetics and sequence development.

Purpose of the Study:

• To explore the emergence of characteristic block lengths over time in stiff copolymers.
• To investigate how activation energy, viscosity, and monomer density affect sequence and block length distributions.
• To understand the influence of emergent aggregation and nematic ordering on chain reactivity and sequence formation.

Main Methods:

• Investigated stiff copolymers undergoing step-growth polymerization.
• Analyzed the impact of varying activation energy, solution viscosity, and monomer density.
• Studied the relationship between reaction kinetics, reactant diffusion, and emergent block lengths.

Main Results:

• Emergent aggregation and nematic ordering restrict longer chain bonding, favoring characteristic lengths.
• Block length distributions become unusually peaked due to length-dependent reaction propensities.
• Characteristic length scales are sensitive to the interplay of reaction kinetics and diffusion.

Conclusions:

• Nematic ordering in stiff copolymers leads to characteristic block lengths, influencing sequence distributions.
• Reaction conditions (activation energy, viscosity) can tune these characteristic lengths.
• Potential exists to control sequence repeats in stiff/semiflexible copolymers via nonbonded interactions and kinetics.