Programmable interfaces: towards reliable and recyclable composite materials via debonding on demand

Introduction

The combination of different materials is often key to the functionality of engineering components. For instance, metal films on polymers are omnipresent composite materials, from food packaging to satellite insulation and flexible electronic displays.

Interface Challenges

Thereby, interfaces are often the weakest link, associated with dissimilar physical properties of adjacent layers or joining parts. A common strategy to prevent interface failure is enhancing adhesion. However, strong (inseparable) interfaces limit recyclability, an aspect largely neglected yet.

Novel Interface Design

Novel interface design could change this situation. This proposal outlines a research program to establish new scientific principles for the nanoscale design of innovative “programmable interfaces” with reliable adhesion in use and thereafter “debonding upon request”, aiming at a new generation of reliable and recyclable sustainable thin film composite devices.

Recent Findings

Recent work of the PI on naturally well-adhering Al on Polyimide (adhesion energy Γ=40 Jm-2) suggests how unique benefits can be mimicked artificially for weak systems (2 Jm-2) via molecular layers (Al-O-C Alucones) deposited at the interface.

Hypothesis

The PI hypothesizes that inseparability of metallization and substrate can be solved by incorporated “triggers” for controlled degradation and delamination in conditions beyond those of standard use, e.g. via local heating at the interface by optical excitation of metallic nanoparticles.

Research Program Overview

“InterBond” shall combine:

1. Fabrication of inorganic-organic model interfaces with triggerable degradation mechanisms.
2. In-situ testing of interface strength in service/trigger conditions.
3. Physical modelling of structural integrity as a function of material combination and architectural design.

Focus and Applications

This research program will focus on interfaces in metal films on polymer, yet the outcomes should apply to lightweight polymer matrix composites with metallic or ceramic fillers, leading the path to sustainable materials for technical applications.