Properties of Mixed Organogelators: Interactions of 9,10-Dihydroxystearic Acid and 12-Hydroxystearic Acid Towards Medium-Chain Triglyceride Oil in Organogel Systems

Abstract

Dihydroxystearic acid (DHSA) has shown promise as a gelling agent for structuring vegetable oils for nonfood applications. However, its use with medium-chain triglyceride (MCT) oil results in weak organogels with low gel strength and soft texture. Therefore, this study aims to improve the DHSA with MCT organogel properties by mixing DHSA with 12-hydroxystearic acid (HSA) in ratios of 100:0, 70:30, 50:50, 30:70, and 0:100 (w/w). The effects of these ratios on physicochemical characteristics, microstructure, mechanical, and thermal properties were systematically examined. An increased proportion of HSA significantly improved oil binding capacity (OBC) with DHSA/HSA, 30:70 (w/w), achieving the highest OBC (99.27%) and hardness (3739.92 g). Microscopic analysis revealed smaller crystal structures and tighter molecular packing at this ratio, contributing to the enhanced mechanical properties. X-ray diffraction and rheological studies further confirmed the formation of a stronger gel network. Fourier transform infrared analysis revealed different dimer formations in DHSA and HSA blends, whereas differential scanning calorimetry indicated a heterogeneous matrix with decreasing melting temperatures (84.5–57.9°C) as the HSA content increased. The adjustable properties of DHSA and HSA organogels offer significant potential for developing stable and durable formulations, presenting new possibilities for cosmetics and pharmaceutical applications.

Practical applications: This study provides a practical strategy for tailoring the performance of medium-chain triglyceride-based organogels by combining dihydroxystearic acid and 12-hydroxystearic acid. The findings provide researchers with guidance for selecting organogelator compositions to achieve properties suited to specific nonfood applications. These design principles can support the development of customized organogel systems as oil-structuring materials for pharmaceutical, cosmetic, and other functional soft material applications requiring tailored mechanical strength, thermal behavior, and formulation stability.