Paper Number
IR27 

Session
Interfacial Rheology

Title
Prediction for the bubble dissolution rate in a protein solution

Presentation Date and Time
October 11, 2022 (Tuesday) 2:30

Track / Room
Track 5 / Sheraton 2

Authors (Click on name to view author profile)

1. Zhong, Xiaoxu (Purdue University, School of Mechanical Engineering)
2. Ardekani, Arezoo (Purdue University, School of Mechanical Engineering)

Author and Affiliation Lines (in printed abstract book)
Xiaoxu Zhong and Arezoo Ardekani
School of Mechanical Engineering, Purdue University, West Lafayette, IN 47906

Speaker / Presenter 
Zhong, Xiaoxu

Keywords
theoretical methods; interfacial rheology; pharmaceuticals

Text of Abstract
Bubbles have many important applications in food science, medicine, chemical engineering, pharmaceutical engineering, etc. Extensive models have been developed to advance the fundamental understanding of bubble dynamics, including gas diffusion, non-equilibrium evaporation and condensation, viscoelastic media, and surface rheology. The protein-coated bubble is also frequently encountered in the pharmaceutical and food industries, but it receives less attention. We have developed a model for the bubble dynamics in a protein solution; the protein-coated bubble surface is modeled as a linear viscoelastic interface. A clean bubble dissolves rapidly in water due to gas diffusion, but we find the surface excess stress stabilizes the protein-coated bubble against dissolution. Initially, the surface excess stress is negligible due to the low protein concentration on the bubble surface. The Weber number, which compares the gas inertial force and the surface tension force, governs the bubble dissolution rate during this stage. As the bubble shrinks, the surface excess stress grows and eventually balances the surface tension. After that, the dissolution rate is governed by the protein desorption rate and the elasto-capillary number, which compares the surface tension and the surface dilatational elasticity. Our model predictions for the dissolution process agree with experiments before the bubble buckles. We have also derived a formula for the bubble dissolution rate, enabling extracting the interfacial parameters from the experimentally measured bubble radii. Our findings indicate that the Maxwell model can characterize the protein-coated bubble surface. This work provides insight into protein-coated bubbles and helps guide the design of protein-coated bubbles, which are used as vehicles to deliver drugs and as active miniature tracers to probe the rheology of soft and biological materials.