Adhesives—A New Open Access Journal

Natural adhesives such as tree resins, gums, and tars have been used since prehistoric times (going back to at least 200,000 years [1]) in applications spanning from building materials and marine structures to household items, tools, paints, ornaments, and artwork [2].

The discovery of macromolecules and the advances in polymer technology [3] meant that it was not only possible to understand and optimise natural adhesives but also to invent novel synthetic adhesives for numerous applications revolutionising construction and a range of technologies affecting our everyday life [4]. The uses vary from adhesive tapes in packaging [5] to the adherence of glass and carbon fibres to manufacture fibre-reinforced polymer (FRP) composites for demanding engineering applications in aeronautical, marine, and renewable energy industries [6,7,8].

Adhesives can be classified into several categories, including stiff structural adhesives (such as epoxy-based thermosets), rubbery or elastomeric adhesives (such as adhesive tapes), thermoplastic hot-melt adhesives (e.g., paper or wood binding), hydrogel-based adhesives (for biomedical applications, e.g., trauma treatment and healing, regenerative medicine, tissue engineering, and bioelectronics), and biological and biomimetic adhesive systems that can work reversibly or irreversibly in wet environments (e.g., geckos, frogs, insects, worms, barnacles, and mussels) [9].

Beyond the traditional macroscopic adhesive tests (peeling, pull out test, stud/butt test, JKR test, lap shear test, tack test, etc.) [10], advances in nanometre-scale interfacial testing based on the surface forces apparatus (SFA) [11] and atomic force microscopy (AFM) force spectroscopy [12,13,14,15] revealed intriguing molecular adhesive mechanisms. Progress in the fundamental understanding of natural and synthetic adhesives provided the means for improved formulations of adhesives [16], and generally the design of superior adhesive joint systems [17]. Continuum mechanics, mesoscale physics, coarse-grained and molecular-scale modelling, analytical theory, and simulations empowered a deeper understanding of the behaviour of adhesives in different scales.

Despite these advancements, the macroscopic measurements are not sufficiently linked to the complex interplay of nanometre-scale physicochemical mechanisms [9]. The effects of surface topography, contact mechanics, surface chemistry, and the large range of spatial and time scales involved in testing and applications of adhesives present major scientific and engineering challenges. The progress in adhesives relies on the concerted multidisciplinary effort involving physics, chemistry, materials science, biology, and mechanical and chemical engineering with applications spanning various sectors such as construction, structural engineering, automotive, aeronautical, renewable energy, and various commodity, household and health products.

The journal Adhesives [18] aims to offer a new space for the fruitful exposition, comparison, and debate of adhesive problems and solutions, including experimental, theoretical, and simulation studies spanning multiple scales, disciplines, and applications of natural, biomimetic, and synthetic adhesives.