Fluoropolymers

Pillow dome built by Jay Baldwin: The Ark houses a growing environment consisting of intensive organic gardens, irrigated by the "exhaust" from large, transparent tanks containing fish. (See aquaponics.) The aquaponic tanks also serve as an effective heat sink, allowing an indoor climate warm enough to grow bananas in February, in New England, with no fossil fuel heat source.

Inside the tropical Biome at Eden Project: The covered biomes are constructed from a tubular steel (hex-tri-hex) with mostly hexagonal external cladding panels made from the thermoplastic ETFE. Glass was avoided due to its weight and potential dangers. The cladding panels themselves are created from several layers of thin UV-transparent ETFE film, which are sealed around their perimeter and inflated to create a large cushion. The resulting cushion acts as a thermal blanket to the structure.

About

High-performance plastic materials such as PTFE ("Teflon") ETFE (Tefzel"). Very interesting properties such as UV resistance, resistance to corrosionfrom most substances and better high temperature performance. Fluoropolymer foil is useful for things like greenhouse covering and for Aluminum Extraction From Clays. The UV resistance of these materials results in long life, with up to 30 years reported with minimal degradation.

Also, UV transmission leads to more "natural" light spectrum inside the greenhouse, suppressing microbes that may otherwise survive if UV light is blocked off. Fluoropolymers are slowly catching on as greenhouse covering but are still much more expensive than current alternatives such as polyethylene and polycarbonate. Drawbacks include susceptibility to puncture holes and movement/wind, which is why fluoroplastic foil is often inflated as cushions (see images: "Pillow Dome" and "Eden Project"). Thicker membranes are possible but much more expensive.

Uses

• greenhouse covering (as foil)