Yao Fu, Shuwen Tan, Xiaojia Xu, Wenlong Xing, Qi He, Yi Lu, Jia Tang, Xiaoyan Liu*, Yu Fang. Carbohydr. Polym. Technol. Appl. 2025, DOI: https://doi.org/10.1016/j.carpta.2025.101037

Emulsions are widely used in different fields, such as food, the pharmaceutical industry, and agriculture. Conventionally, emulsions are stabilized by surfactants; however, these compounds pose risks to water resources, environmental ecosystems, and human health due to their persistence and potential toxicity. Pickering emulsions have attracted extensive attention owing to their excellent interfacial stability and eco-friendliness. However, achieving precise control over their structures and imparting intelligent responsiveness still represents a major challenge in the contemporary field of functional materials.

To address these challenges, we, for the first time, prepared pH and temperature dual-responsive P(VCL-co-SA) microgels via free-radical precipitation polymerization method. Compared with other methods such as microfluidics and emulsion templating, the present polymerization approach is relatively simple and yields alginate-based microgels with uniform size. The obtained P(VCL-co-SA) microgels demonstrated high interfacial activity at the dodecane/water interface, enabling the stabilization of dodecane-in-water emulsions across a broad pH range (3–9) at 25 °C. At an elevated temperature (55 °C), the emulsions remained stable at pH 6 and 9 (above the pKa of alginate, ~3.5), while phase separation was observed at pH 3 below the pKa.

图1 微凝胶颗粒的水接触角及界面张力

The emulsion stability was further enhanced by optimizing Ca²⁺ ion concentration. Furthermore, the high internal phase soybean oil-in-water emulsion stabilized by P(VCL₈₃-co-SA₁₇) microgels exhibited a curcumin encapsulation efficiency of nearly 100% and provided excellent protection at room temperature. When incubated at 37 °C for 24 hours, curcumin retention was significantly enhanced after the addition of Ca²⁺ ions, increasing it from 44.9% to 54.7% at pH 3 and from 62.5% to 76.8% at pH 7.

图2 大豆油/水乳液中姜黄素的包封效率和保留率

These findings demonstrate the considerable potential of this emulsion system for delivering bioactive compounds, paving the way for developing safer and more efficient carrier systems in the food and pharmaceutical industries.

First Author: Fu Yao, master’s student, Shaanxi Normal University

Correspondence Author: Assoc. Prof. Liu Xiaoyan, Shaanxi Normal University

Full Text Link: https://doi.org/10.1016/j.carpta.2025.101037