History of Adhesives

Adhesives are the diplomats of the polymer world. They exist for the purpose of bringing other materials together; their success is measured by the production cost, properties, and permanence of the assembly. Historically, the starches, protein glues, and natural rubber were supplemented or replaced by phenolics and amino resins for plywood and particleboard; synthetic rubbers for construction, textile bonding, and pressure-sensitives; poly-vinyl acetate for packaging, gypsum board, and the home handy-person's “white glue”; hot melts for bookbinding. Three of the newer families of adhesives are outstanding in performance: the epoxies; the isocyanates and polyurethanes; and the versatile acrylics, including the spectacularly growing cyanoacrylates and anaerobics. They are especially useful for the bonding of metals, synthetic fibers, plastic film, and other “difficult” substrates in product assembly, aerospace, textiles, construction, furniture, film laminates, and pressure-sensitives. Synergism and hybrid functionality are hallmarks of many of the new adhesives. Controlled cross-linking, improved adhesion, and other characteristics are attained through adroit blending of functional groups: vinyl unsaturation, carboxyl, glycidyl, hydroxyl, isocyanate, and methylol amide.     

Transitions of Collective Motions Driven by Phase Resetting

The front cover artwork is provided by Prof. Gao's group. The image shows the motion patterns transition of the active gel group under the step light intensity, which describes the mechanism of a new collective emergence structure. Read the full text of the Research Article at 10.1002/cphc.202300054 .