Polarization model for poorly-organized interfacial water: hydration forces between silica surfaces

Area of Science:

• Colloid and Surface Science
• Physical Chemistry
• Materials Science

Background:

• Understanding silica surface interactions is crucial for various applications.
• Existing theoretical models often struggle to simultaneously explain double layer and hydration forces.
• Experimental data on silica surface forces require refined theoretical frameworks.

Purpose of the Study:

• To review theoretical models for silica surface interactions.
• To demonstrate the adaptability of the authors' polarization model to experimental findings.
• To investigate the role of interfacial water structure and gel layers in surface forces.

Main Methods:

• Theoretical review of interaction models.
• Application and adaptation of the polarization model.
• Analysis of dipole correlation length (lambda(m)) under different water structuring assumptions.
• Phenomenological fitting of the polarization model using lambda(m) as a parameter.

Main Results:

• The polarization model, incorporating double layer and hydration forces, can explain experimental silica surface interactions.
• An ice-like water structure leads to long-range forces, exceeding experimental observations.
• A silica gel layer likely disorders interfacial water, reducing the dipole correlation length (lambda(m)).
• Fitting lambda(m) to ~4 Angstrom yields good agreement with experimental data.

Conclusions:

• The polarization model provides a robust framework for understanding silica surface forces.
• Interfacial water structure and potential gel layers significantly impact surface interactions.
• The model's phenomenological application, using lambda(m) as a fitting parameter, offers a practical approach to experimental data interpretation.