Adhesive joining has displaced mechanical fastening in a growing share of aerospace, biomedical, electronic and architectural assemblies, mainly because bonded joints spread load more evenly, add little weight and tolerate dissimilar adherends. The reverse operation, separating the adhesive again without marking the part underneath, has attracted far less attention, and it becomes particularly awkward when the substrate is smooth: a polished metal coupon, a float-glass pane, a thinned silicon wafer or an optical-grade polymer presents a uniform, defect-free interface that offers none of the stress concentrators most debonding processes rely on. Removal procedures chosen without regard for the adherend leave micro-scratches, thermally altered layers, chemisorbed residues or dimensional drift, all of which shorten the service life of the recovered component. In this work, we systematically reviewed the literature on mechanical, thermal, chemical, electrochemical and hybrid debonding and assessed each family against the condition of the recovered substrate rather than against removal speed alone. Surface roughness, subsurface hardness, residual stress, chemical state and wettability were adopted as the assessment framework, and the available characterization techniques were compared by the depth of material each actually interrogates. Across the studies surveyed, laser and laser-chemical hybrid routes returned the closest match to the pre-bonding baseline, with roughness increments of roughly 0.05–0.10 µm on metals and composites and below 1 nm in wafer-level release, whereas mechanical scraping produced the largest degradation, up to about 2.3 µm. Chemical routes avoid mechanical damage but leave carbon-rich films that only surface-sensitive spectroscopy detects. We argue that the absence of an agreed post-debonding evaluation protocol, rather than any shortage of removal techniques, is now the main obstacle to progress in the field, and we indicate where responsive adhesives, inline verification and greener chemistries are most likely to develop.
