Adhesive curing through low-voltage activation.

Jianfeng Ping,Richard D Webster,Jian Lin Chen,Terry W J Steele,Feng Gao

doi:10.1038/ncomms9050

Jianfeng Ping, Richard D Webster + Show 3 more

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https://doi.org/10.1038/ncomms9050

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Abstract

Instant curing adhesives typically fall within three categories, being activated by either light (photocuring), heat (thermocuring) or chemical means. These curing strategies limit applications to specific substrates and can only be activated under certain conditions. Here we present the development of an instant curing adhesive through low-voltage activation. The electrocuring adhesive is synthesized by grafting carbene precursors on polyamidoamine dendrimers and dissolving in aqueous solvents to form viscous gels. The electrocuring adhesives are activated at −2 V versus Ag/AgCl, allowing tunable crosslinking within the dendrimer matrix and on both electrode surfaces. As the applied voltage discontinued, crosslinking immediately terminated. Thus, crosslinking initiation and propagation are observed to be voltage and time dependent, enabling tuning of both material properties and adhesive strength. The electrocuring adhesive has immediate implications in manufacturing and development of implantable bioadhesives.

Highlights

Instant curing adhesives typically fall within three categories, being activated by either light, heat or chemical means
Instant fixation is of prime importance, especially if one seeks to replace laborious mechanical fixation techniques such as rivets, screws, and bolts
Despite the importance of instant fixation, little innovation in terms of stimuli activation has been accomplished in the past few decades and most current Chemical-curing adhesives (CCA) technologies are activated by either temperature, light, or two-part thermosets

Summary

Introduction

Instant curing adhesives typically fall within three categories, being activated by either light (photocuring), heat (thermocuring) or chemical means. As the voltage surpasses this threshold, electrochemically activated functional groups are switched ‘on’ and able to crosslink the polymer backbone and substrates that they are to be adhered to This crosslinking would be arrested once the voltage falls below a threshold, allowing the end-user to modify both the bonding strength and adhesive material properties. This type of control would surpass current chemical-curing adhesives. Electrocuring adhesives would solve many of the limitations described above They could be utilized on heat-sensitive materials, contain no sensitizing initiators, and their potential versatility may be perfect for in-line manufacturing. They are ideal for automation adhesive applications (extrusion on a molded part, thin-film tapes and so on), as electrocuring is separated in two distinct phases without the maintenance-intensive hardware associated with thermo-/photocuring, or two-part adhesives

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