iCVD Solid Nanoadhesives for Precision Assembly at Near Room Temperature*

Adhesives are widely used in manufacturing processes to bond components. Due to their ubiquity in consumer goods, adhesives and sealants form a mature $50B industry with decades of investment in formulation chemistry for various applications. However, nearly all adhesives are based on the application of viscous resins which cure based on chemical reaction, solvent evaporation, or cooling of a hot melt. Capillary forces from liquid-like resins both prevent the formation of thin (<1 μm) bondlines and can wick or damage porous materials such as foams, aerogels and other delicate structures at the nano and microscale.
Here we synthesized adhesive solid polymers directly from vapor-phase reagents by initiated chemical vapor deposition (iCVD) avoiding any liquid intermediates while achieving thickness control within tens of nanometers. We formulated thermoplastics that bond physically rather than chemically by inducing polymer chain interdiffusion when the polymer is heated above its glass transition temperature, T_g. Whereas chemical cure near room temperature requires liquid-phase metal catalysts or UV light, this approach allows to engineer T_g via polymer composition.