Tack of Entangled Molecular Bottlebrushes

Polymer softness (i.e., low elastic modulus) is a known requirement for good tack in adhesives. We assess the tack performance of alpha-olefin molecular bottlebrushes having an elastic modulus from 4 to 30 times lower than a linear polyolefin (polypropylene). Monotonic increases of the tack parameters are observed as the bottlebrush side chain length (Nsc) increases and the modulus decreases. All-atom molecular dynamics simulations reveal that the monomeric bonding energy increases with Nscdue to a strong van der Waals interaction between the side chains and the aluminum sheet, which overcomes the energy penalty imposed by side-chain bending.

Automated summary

This study evaluates the tack performance of alpha-olefin molecular bottlebrushes with an elastic modulus 4 to 30 times lower than linear polyolefin (polypropylene). The results show that the tack parameters increase monotonically with the increase of bottlebrush side chain length (Nsc) and the decrease of modulus. All-atom molecular dynamics simulations reveal that the monomeric bonding energy increases with Nscdue to a strong van der Waals interaction between the side chains and the aluminum sheet, overcoming the energy penalty imposed by side-chain bending.