In a significant stride towards advancing energy materials, researchers have developed a novel approach to create thermally stable, ethanol-based gel fuels with tunable mechanical properties. The study, led by Alessia De Cataldo from the Aerospace Sciences and Engineering Ph.D. program at the Polytechnic of Bari and University of Bari Aldo Moro in Italy, introduces a method to enhance ethanol retention and thermal stability in ethyl cellulose (EC) gels using calcium chloride (CaCl2). The findings, published in the journal “Academia Materialium” (English: “Academia of Materials”), open new avenues for energy materials and propulsion-related applications.
The research focuses on the fabrication of ethanol-based EC gels, which typically form viscous liquids. However, the incorporation of CaCl2 induces gelation, creating a robust polymer network through ionic coordination with ethanol and cellulose chains. This process results in a gel with remarkable properties. “The key to our success lies in the synergistic mechanism of ionic coordination,” explains De Cataldo. “By optimizing the ratio of EC to CaCl2, we can engineer gels with tailored viscoelasticity and enhanced thermal resistance.”
The optimized gel, designated as EC100s50, exhibits a true gel state with a yield stress of approximately 115 Pa and shear-thinning behavior. Phase-contrast microscopy revealed a homogeneous, interconnected network, while thermogravimetric analysis showed enhanced ethanol retention, with delayed evaporation up to 165 °C and single-step EC decomposition occurring at 312 °C. The activation energy for EC decomposition in the optimized sample (EC90s45) reached 185 ± 15 kJ mol−1, significantly higher than that of pure EC. Despite the enhanced stability, ethanol was still released for ignition, with an activation energy of 45 ± 4 kJ mol−1 and a total combustion energy density of 29.3 kJ g−1.
The implications of this research for the energy sector are profound. The ability to engineer soft-solid ethanol–EC gels with tunable viscoelasticity and thermal resistance offers potential for advanced functional materials in energy storage and propulsion systems. “This technology could revolutionize the way we think about gel fuels,” says De Cataldo. “The enhanced stability and controlled release of ethanol make these gels ideal candidates for a wide range of applications, from portable energy sources to advanced propulsion systems.”
The study’s findings suggest that CaCl2-assisted ionic coordination is a promising strategy for developing next-generation energy materials. As the demand for efficient and sustainable energy solutions continues to grow, this research provides a crucial stepping stone towards achieving these goals. The publication in “Academia Materialium” underscores the significance of this work, highlighting its potential to shape future developments in the field of materials science and energy technology.