TITLE:
Experimental and Correlative Analysis of Viscosity, Surface Tension, and Rheological Properties Influencing E-Liquid Leakage
AUTHORS:
Madhumathi Mani, George Easdown, Antonia Soqaka
KEYWORDS:
E-Liquids, Propylene Glycol (PG), Vegetable Glycerin (VG), Leakage, Formulation
JOURNAL NAME:
Open Journal of Applied Sciences,
Vol.16 No.4,
April
30,
2026
ABSTRACT: The increasing use of e-cigarettes underscores the importance of understanding the physicochemical properties of e-liquids—particularly viscosity, surface tension, and rheological behavior—as these parameters influence leakage performance and user experience. This study evaluated the interrelationship among viscosity, surface tension, and storage modulus (G') across PG, VG, water, and standardized PG/VG mixtures, and examined how these properties contribute to leakage tendencies under controlled thermal and vacuum conditions. Surface-tension values ranged from 37 mN/m (PG) to 64 mN/m (VG), with PG/VG blends predominantly falling within a moderate intermediate range (39 - 47 mN/m), aside from two deviations at 90:10 (54.24 mN/m) and 50:50 (42.82 mN/m). Conversely, viscosity and G' increased consistently with VG content, strongly reducing leakage risk, while PG-rich blends demonstrated lower viscoelasticity and higher leakage susceptibility. These findings indicate that viscosity and elasticity are the primary determinants of leakage, whereas surface tension plays a secondary role. The work provides a quantitative foundation for optimizing PG/VG ratios in commercial e-liquid formulations to enhance device reliability.