Date on Master's Thesis/Doctoral Dissertation

8-2019

Document Type

Master's Thesis

Degree Name

M. Eng.

Department

Mechanical Engineering

Committee Chair

Williams, Stuart

Committee Co-Chair (if applicable)

Brehob, Ellen

Committee Member

Brehob, Ellen

Committee Member

Willing, Gerold

Author's Keywords

Whiskey webs; chaotic ethanol evaporation; sessile droplet; Colloidal self-assembly; monolayer collapse; coffee-ring effect

Abstract

The recent discovery of the unique structures, whiskey webs, formed when the evaporation of diluted American whiskey, has raised many questions as to the nature of the structures. Their formation process follows as such: (1) dilution of the whiskey to form nanoaggregates, (2) formation of a monolayer at the air-liquid interface, (3) chaotic ethanol evaporation caused monolayer collapse (via dynamic pressure), (4) bulk fluid evaporation caused monolayer collapse (via reduction of surface area), where the web-like structures reside on the surface, and finally, (5) web-like structures deposit on the substrate. The webs imaged via SEM had a striking resemblance to the “twisted ribbon fold” found in literature. There has been significant research within monolayer collapse where various mechanisms have been found which describe how they collapse; this work focused on the role of ethanol evaporation of sessile droplets in the formation of whiskey webs. The study will identify how characteristics (maturation, proof, surfactants, filtrations, congeners, and whiskey web patterns) influence the fluid velocity to the greatest degree. Since the ethanol evaporation is believed to be the largest contributor to the web-like structure formation process, it was studied here. This work will help to understand the role the ethanol evaporation has to the uniqueness of the web structures. These findings contribute towards correlating monolayer collapse mechanisms and feature characteristics to the intrinsic properties within American whiskey.

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