Reversal of Scratches in Polymer Seals via Laminated Vascular Networks

Abstract

Ball valve seats are subject to relative sliding motion during opening and closing making them susceptible to accelerated wear from particles entrapped in the ball-seal interface. The resulting wear channels can lead to a poor seal, sometimes resulting in valve failure, which would necessitate repair or replacement of the valve. Self-healing techniques offer a potential method for autonomously repairing seal leakage that results from abrasive damage. In this work, a microvascular approach is adopted to automatically repair ball valve seats and reduce leakage. Healing is accomplished by circulating healing chemistry through small channels isolated from the environment by a thin surface laminate in order to simulate progressive seal damage due to abrasion. Self-repair is accomplished by autonomously filling surface scratches with a healing agent. The healing agent performs a dual purpose of slowing down the damage rate by lubricating the surface as well as reversing the loss of material by polymerizing to form new material. Manufacturing techniques of microchannels are developed for Polymethylmethacrylate (PMMA, Acrylic) and Polyoxymethylene (POM, Delrin), and wear resistances are measured.