What Makes a Designer Solvent Efficient for Capturing Volatile Organic Compounds?—A Molecular Perspective

Designer solvents (DSs), particularly room-temperature ionic liquids (RTIL) and deep eutectic solvents (DES), have emerged as promising alternatives for capturing volatile organic compounds (VOC), addressing the limitations of conventional mitigation strategies. The tunability of DSs-achieved via functional group modification, hydrogen bond donor-acceptor pairing, and incorporation of supramolecular additives-was found to be key in optimizing VOC solubility and retention. Beyond bulk absorption, DSs have also been shown to enhance VOC uptake in porous hybrid materials, underscoring their role in integrated capture systems. Despite these advances, molecular-level understanding of VOC-solvent interactions remains fragmented, limiting predictive design. In this perspective, we summarize key experimental and computational insights that have advanced the molecular understanding of VOC absorption in DSs. Drawing upon our past molecular dynamics (MD) studies and related literature, we highlight how interfacial structuring, solvation thermodynamics, and donor-acceptor chemistry dictate the efficiency of RTIL and DES. Comparative analysis between these solvent families provides a framework for identifying optimal VOC-specific DSs. We conclude by outlining emerging research directions where synergistic experimental-computational approaches can accelerate the rational development of green solvent technologies for air-quality management and emission control.