C011 -- Self-Healing Barrier Films for Vacuum Insulation Panels

Vacuum insulation panels (VIPs) provide highly efficient thermal insulation by evacuating the core to eliminate gas conduction. VIPs with fumed silica cores can achieve R-~35/inch (~273 mK/W), ~4 times higher than that of current building insulation materials, such as cellular foams and fiberglass. Despite such excellent thermal insulation property, limited durability of VIPs is limiting their widespread deployment because of the risk of damage to the barrier films during handling, transportation, and primarily installation. Thus, this project has developed multi-layered barrier films with self-healing capability that can seal cuts and punctures and maintain the impermeability of the barrier films. Such self-healing barrier films will enable VIPs to retain their internal vacuum and low thermal conductivity even if the barrier film is cut or punctured. The two-part self-healing chemicals (amine and epoxy) are placed in a separate layer in the multi-layer barrier film, so that the damage to the film allows to mix and react the two-part chemistry for healing. The self-healable multi-layered barrier films were successfully fabricated by a roll-to-roll manufacturing. The puncture tests on the fabricated multi-layered films were conducted using a needle and a screw to evaluate the efficacy of the self-healing reaction to maintain the internal vacuum level. The tests showed that the self-healing reaction happened rapidly, and the healed films maintained the system’s vacuum. In comparison, control multi-layered films without the self-healing layers allowed the system pressure to rise to atmospheric levels within minutes on puncturing. Furthermore, a small prototype VIP was fabricated using the developed self-healing barrier films. The VIP with the self-healing barrier films successfully demonstrated to maintain R-value after a puncture by a nail. This study has demonstrated that self-healing chemistry can be used to repair puncture/damage to barrier films and maintain the high thermal insulation performance of VIPs.