Design strategies for engineering soluto-inertial suspension interactions

Area of Science:

• Colloidal science
• Materials science
• Physical chemistry

Background:

• Soluto-inertial (SI) interactions enable long-range transport of colloidal particles.
• These interactions rely on solute fluxes generated by specialized "beacons."
• Diffusiophoresis (DP) is the mechanism by which particles migrate in response to these solute fluxes.

Purpose of the Study:

• To present a general strategy for designing and predicting soluto-inertial interactions.
• To explore two classes of SI beacons: solute-partitioning and solute-associating.
• To develop a framework for understanding beacon-solute pair interactions and their impact on particle transport.

Main Methods:

• Identification of key design parameters for SI beacon systems.
• Construction of a parameter space map for SI interactions.
• Calculation of characteristic timescales for solute flux persistence.
• Derivation of analytical expressions for solute concentration profiles.
• Prediction of colloid diffusiophoretic velocity based on beacon type (source vs. sink).

Main Results:

• A systematic approach to designing and predicting SI interactions is established.
• Characteristic timescales for SI flux persistence were calculated.
• Analytical expressions for solute concentration profiles were derived.
• Qualitative differences in colloid migration were observed between solute-releasing (source) and solute-absorbing (sink) beacons.
• Proof-of-principle experiments validated the findings for both partitioning and associating beacon types.

Conclusions:

• The developed strategy provides a robust framework for designing and predicting soluto-inertial interactions.
• The findings offer insights into controlling colloidal particle transport using engineered beacons.
• The conceptual approach is adaptable to a wider range of materials and SI interaction mechanisms.