SeLf-powered self-rEshaping Autarkic skin For wireless motes - LEAF

Introduction

We will combine 3D reshaping, energy harvesting, and energy storage within a single, thin foil. The thin foil of several micrometers thickness is going to be fabricated by inkjet and capillary printing on a temporal carrier support.

Fabrication Process

The foil consists of:

• An adhesion sacrificial layer (own technology relying on lanthanum acrylic acid coordination polymer).
• A strain-inducing bilayer made of hydrogel and a stiffening layer (own innovation technology).

The combination of specifically designed bilayer polymer system (polyethylene alt maleic anhydride type hydrogel and polyimide materials) is able to reshape into Swiss-roll architectures with few hundreds of micrometer diameter through:

1. Selective etching of the sacrificial layer.
2. Swelling of the hydrogel in a water-based solution.

High Precision Capillary Printing

We will implement high precision capillary printing (HPCAP) to print dedicated structures with:

• High control over length, thickness, and separation.
• (Sub-)micrometer resolution.
• High reproducibility of a variety of materials, which deliver different functionality.

Self-Powering Mechanism

Self-powering of the autonomous device is ensured through the use of bi-functional materials deposited into interdigitated micro-electrode structures, which function as:

• Light converters.
• Storage materials at the same time.

The thus created photo-storage microscale supercapacitor is embedded onto the thin foil and will serve as an autonomous power source for the integrated silicon chip.

Design and Functionality

The 2D area of the ultrathin foil delivers maximized surface area of the interdigitated finger structure and ensures sufficient light absorption to power the integrated RFIC (e.g., an active tag/sensory system).

Weight and Stability

The optimized weight (R ~ 0.95) will be granted by the ultrathin nature of the foil (around 5μm), while mechanical stability of the final device is ensured through 2D-to-3D reshaping.

Key Features

A key feature of our final device is the ability to retain its functionality also after 3D reshaping and its deployment onto the application surface.