Switchable Coacervate Adhesives to Engineer Coating Adhesion and Release

Objective

Conventional coatings face a fundamental trade-off between adhesion and removability: peelable layers sacrifice bonding strength, while coatings with permanent adhesion require toxic, costly, or destructive removal processes. This limitation not only hinders substrate recyclability but also increases environmental impact and processing costs. The SWITCHCOAT project aim to break this barrier by developing a dual-layer coating system with switchable adhesive strength using a novel coacervate adhesive layer that is strongly anchored to substrates. The coacervate adhesive layer design will allow debonding through dehydration and include a top liquid-repellent layer (LRC) that both protects the coacervate layer and provides functionality. I will focus the coacervate layer design with a tailored affinity linked to LRC and both for hydrophobic and hydrophilic substrates. Interfacial adhesion between the substrate, coacervate, and LRC layers will be quantitatively measured using Scanning Droplet Adhesion Microscopy (SDAM), which allows both force measurements and visualization of interface dynamics during bonding and debonding. Complementary Photo-Induced Force IR spectroscopy (PiF-IR) will provide spatially resolved and molecular-level insights into interfacial interactions. I will then evaluate the physicochemical stability. Finally, I will explore the controlled dehydration condition for on-demand removal. The anticipated outcome of SWITCHCOAT is a sustainable coating technology capable of delivering strong bonding during use (>10 J/m²) while allowing on-demand debonding (<1 J/m²). This innovation enables recyclable substrates, reduces environmental impact, and advances high-performance coating applications across diverse industries (e.g. biomedicine), while providing a mechanistic understanding of multilayer adhesion by linking molecular-scale interactions to macroscopic adhesion. It has broad relevance to soft materials, surface and interfacial science.