Spider Silk Inspired Processing of Liquid Crystalline Complex Coacervates

Area of Science:

• Materials Science
• Biomaterials Engineering
• Polymer Chemistry

Background:

• Spider silk spinning involves coacervation and liquid crystalline domain organization.
• Shear forces and salt concentration are critical for fiber alignment in natural silk.

Purpose of the Study:

• To develop a synthetic system mimicking spider silk's hierarchical organization and alignment.
• To investigate the role of salt concentration and shear in controlling coacervate liquid crystalline states and fiber formation.

Main Methods:

• Utilized liquid crystalline complex coacervates.
• Varied salt (tetrabutylammonium bromide, TBAB) concentrations and applied shear forces.
• Employed rheological and X-ray scattering measurements.
• Demonstrated alignment via stretching and 3D printing.

Main Results:

• Salt concentration dictates the balance between isotropic and liquid crystalline states (coacervation suppressed >0.5 M TBAB, smectic order ≤0.2 M TBAB).
• Higher salt concentrations accelerate molecular relaxation and increase the shear rate threshold for ordering.
• The salt-shear interplay controls viscoelastic response and molecular anisotropy.

Conclusions:

• Synthetic coacervates replicate spider silk's hierarchical organization and alignment mechanisms.
• Tunable salt concentration offers precise control over processability and shear-induced alignment.
• This biomimetic approach provides a powerful route for designing anisotropic materials.