Ionic liquid capsules for cold-resistant leathers: connecting the three pillars of green chemicals, clean processes and green products

Abstract

The convergence of green chemistry, resource-efficient processing, and eco-designed leather products underscores a transformative pathway toward globally recognized standards of sustainable production. The manufacture of traditional leather chemicals relies on petroleum-based surfactants and separate re-tanning and fatliquoring steps, making it resource-intensive and environmentally unsustainable. This study introduces a green chemistry route for sustainable leather processing by designing cholinium oleate, a bio-based ionic liquid, as a non-toxic emulsifier for silicone oil and its subsequent encapsulation into silica nanocapsules. The resulting multifunctional capsules simultaneously act as re-tanning agents, fatliquors, fillers, and phase-change materials, eliminating the need for multiple synthetic auxiliaries, offering cold-insulation and cold-crack resistance at low temperatures (−20 °C). The process demonstrates significant reductions in water use (41.22%), surfactant dosage (57.69%), and energy input (29.3%) while operating under mild conditions. By integrating eco-friendly chemicals with process intensification, this approach advances cleaner chemistry, reduces environmental burdens, and delivers durable, cold-resistant leathers that align with the principles of sustainable manufacturing.