Paper Number
IR31 

Session
Interfacial Rheology, Surfactants, Foams, and Emulsions

Title
Unique rheology of self-degrading gel foams: Transitioning from liquid to solid to liquid

Presentation Date and Time
October 15, 2024 (Tuesday) 4:45

Track / Room
Track 6 / Room 501

Authors (Click on name to view author profile)

1. Burni, Faraz A. (University of Maryland, Chemical and Biomolecular Engineering)
2. Raghavan, Srinivasa R. (University of Maryland)

Author and Affiliation Lines (in printed abstract book)
Faraz A. Burni¹ and Srinivasa R. Raghavan^2
1Chemical and Biomolecular Engineering, University of Maryland, College Park, MD 20910; ²University of Maryland, College Park, MD 20740

Speaker / Presenter 
Burni, Faraz A.

Keywords
experimental methods; colloids; emulsions; foams; gels; networks; polymers; surfactants

Text of Abstract
Gel foams combine the advantages of gels and foams, showing promise in fire prevention and combating harmful algae blooms. This study presents an innovative approach to create a solid gel foam from a thin precursor solution that degrades back to a low-viscosity liquid after a set time. Foam is a two-phase system consisting of gas dispersed within a continuous liquid phase. In this study, the liquid phase includes surfactant and gelling agents. These foams are formed through a gelling reaction between poly(ethylene glycol) diacrylate (PEGDA) and poly(ethylene imine) (PEI), which degrade over time due to the hydrolysis of ester groups. Gas bubbles are generated through hydrogen peroxide decomposition, producing a highly porous, low-density gel foam. Initially, the precursor solution exhibits low viscosity, allowing significant expansion upon deployment, followed by gelation to form a solid foam with gel-like rheology (G' > G'' and frequency-independent moduli). One key application of these self-degrading foams lies in preventing harmful algae blooms. These foams can be loaded with an algaecide and, when deployed, quickly expand to cover large surface areas of water, followed by rapid solidification. This ensures the foam remains on the surface and does not mix with the water below. The algaecide is slowly released via diffusion, targeting algae near the surface while minimizing impact on marine life below. After the treatment period, the foam self-degrades, eliminating the need for post-cleanup. Degradation kinetics can be precisely controlled through the composition of the foam. This allows for easy algae bloom treatment followed by self-elimination of the foam, thus advancing cost-effective and environmentally sustainable practices.