Biosynthetic Polyelectrolyte Composites Exhibit Tunable Scale-Dependent Mechanics Governed by Entanglements

Area of Science:

• Polymer Science
• Materials Science
• Biophysics

Background:

• Biological DNA and synthetic polymers are key components in advanced materials.
• Understanding their composite behavior is crucial for developing novel applications.
• Tuning physical properties of polymer composites is essential for specific functionalities.

Purpose of the Study:

• To engineer miscible composites of DNA and sodium poly(styrenesulfonate) with tunable physical properties.
• To investigate the influence of DNA fraction and ionic strength on composite dynamics.
• To explore the potential of these composites in applications like energy storage and drug delivery.

Main Methods:

• Formation of interpenetrating polymer networks of DNA and synthetic polymers.
• Characterization of solution properties across semidilute to entangled regimes.
• Analysis of viscosity and dynamics at varying DNA concentrations and ionic strengths.

Main Results:

• DNA entanglement concentration dictates the transition from semidilute to entangled dynamics.
• Viscosity transitions from polyelectrolyte to good solvent scaling with increasing DNA fraction and ionic strength.
• Short spatiotemporal dynamics consistently follow theta-solvent scaling.

Conclusions:

• Combining biological DNA and synthetic polyelectrolytes allows independent tuning of key properties.
• This approach enables engineering of polymer composites with broad dynamic range and responsiveness.
• Potential applications include advanced energy storage and targeted drug delivery systems.