In an exploratory experiment, utilizing a flow visualization technique, a droplet of water was supplemented with fiber and released into a container of liquid. The liquid inside container consisted of a thin layer of oil laid on top of the water, in which a small amount of bromothymol-blue indicator was added. The liquid droplet also contained a dilute solution of NaOH along with the small amount of fiber supplement. Thus, as the droplet dived through the two immiscible layers, the path of the diffused droplet exhibited a dark blue color due to its greater pH.
It was found that due to the weight of the added fiber, the drop began to form an inverted mushroom. Then, the weight continues to pull the droplet to the bottom of the container where the fiber-enhanced liquid rotates in a circular path. A portion of fiber remains latched onto the oil layer, which sustains the diffusing fiber stretching into a single, straight line filament. Yet, over time the straight filament began to buckle and bend. Over time, the droplet became increasingly unstable prior returning to a single filament once more. This transformation was evidenced until the deep blue faded as the pH level diffused. An additional experiment was carried out using a larger droplet. The droplet with a larger surface area reacted similarly, but passed the oil/ water interface at multiple contact points, as opposed to a sole point. Subsequently, multiple bending filaments appeared in the liquid. In time these filaments combined into a distinct, deformed, filament. After which, the continued instability of the filament broke into two segments, that with time became orderly. In the end, a pair of filaments was formed from the larger fiber-laced droplet.
The idea of controlling drug delivery has been studied from a plethora of angles, however, how a drug diffuses with the addition of fiber has not often been visualized. This visual investigation will establish the fundamental physics that is a critical first step in the ability to understand, predict and control the motion of a fiber enriched liquid droplet releasing into another liquid. It is of fundamental importance to the medical field and beyond if the addition of a fiber solution can influence medicine, or a solution, to reach a particular location.
Further research on this topic would involve the effect of fluid viscosity and surface tension to improve drug delivery.