Helix--rod transition in a nanospring

Area of Science:

• Soft matter physics
• Nanotechnology
• Physical chemistry

Background:

• Helical nanosprings are crucial in various applications.
• Understanding nanospring behavior requires analyzing interparticle forces.

Purpose of the Study:

• To model a helical spring whose dimensions are governed by competing forces.
• To investigate the stability of nanosprings under varying electrostatic conditions.

Main Methods:

• Developed a theoretical model for helical nanosprings.
• Incorporated van der Waals, hydration, and electrical double-layer forces.
• Accounted for electric contribution to curvature free energy.

Main Results:

• Nanospring pitch and length are determined by the balance of attractive and repulsive forces.
• Nanospring stability is compromised by increased electrostatic repulsion.
• A critical repulsion limit triggers instability, causing a jump to an extended state and a viscosity jump in suspensions.

Conclusions:

• The model provides insights into nanospring behavior and stability.
• Electrostatic repulsion plays a critical role in nanospring dynamics.
• The observed phenomena have implications for suspensions containing nanosprings.