Valence-induced jumps in coacervate properties.

Area of Science:

• Polymer Science
• Materials Science
• Biophysics

Background:

• Spontaneous phase separation (coacervation) is key for assembling natural and synthetic materials.
• Understanding coacervation triggers is crucial for material design and understanding biological processes.

Purpose of the Study:

• To highlight two critical triggering phenomena in coacervation.
• To investigate the impact of charge addition on polyelectrolyte coacervate systems.
• To explore a novel viscoelastic transition in charged systems.

Main Methods:

• Investigated phase transitions in polyelectrolyte coacervates with small molecules.
• Studied the effect of adding one to two charges per molecule on phase separation.
• Analyzed changes in coacervate modulus and viscosity upon charge addition.

Main Results:

• Addition of one to two charges per molecule induced a transition from a mixed to a two-phase system.
• A significant jump in coacervate modulus and viscosity was observed with one additional charge in a three-charged system.
• This jump represents a previously unidentified viscoelastic transition.

Conclusions:

• Minimal charge addition can dramatically alter coacervate phase behavior and material properties.
• The discovered viscoelastic transition has implications for diseases involving abnormal mechanical properties and irreversible assembly.
• Coacervation science offers tunable mechanisms for material assembly with potential biomedical applications.