Class of Cross-Linkers That Self-Extract via Thermodynamically Driven Phase Transfer for Energy-Efficient Recycling

Degradation of polymers for recycling generates mixtures of molecules. Molecular separation is needed for many applications of individual molecules. However, molecular separation is challenging, especially for recycling. This study reports on a general class of molecules ("Poly-Linkers") that act as cross-linkers for forming macroscale solid polymers and have the chemical functionality to perform molecular separation for recycling. They do not resemble typical cross-linkers; instead, they include common molecules (e.g., fatty acids) with diverse molecular structures and applications. The polymers have general and unique applications, including the simple fabrication of drug-loaded core-shell particles due to the dual roles of ibuprofen as both the drug and Poly-Linker. Besides minimal energy required for de-cross-linking, both molecular separation and formation of the macroscale polymers are driven by favorable thermodynamics and occur spontaneously without energy. Therefore, performing the entire cycle of recycling of these polymers is energetically efficient and simple.