Analysis of Endoscopic Injectability and Post-Ejection Dripping of Yield Stress Fluids: Laponite, Carbopol and Xanthan Gum

摘要

Yield stress uids, which show reversible gel–sol transition and a decrease in viscosity via shear, are expected for en doscopic applications. However, quantitative analyses of such uids, including pressure drop during endoscopic cath eter delivery and post-delivery dripping, have not yet been conducted from a chemical engineering perspective. In this study, we fabricated an equipment setup comprising an endoscopic catheter and a model gastrointestinal (GI) duct to which di erent concentrations of three model yield stress uids, specically, laponite (LAP), Carbopol (CP), and xanthan gum (XG), were applied and compared. We claried the tradeo between the pressure drop through the catheter and dripping on the GI duct model. In terms of operability, LAP performed better than CP and XG. The e ect of gravity on dripping, which is greatly a ected by the position of a patient, was discussed. Finally, the relationship between the operability and rheological properties such as viscosity, yield stress, and restructuring time of the three materials were quantitatively studied.