Materials for Inflatable Membrane Structures

Introduction

The membrane is the absolute core of an inflatable membrane structure. It not only bears the structural load but also possesses multiple functions, such as weather resistance, sealing, and self-cleaning. Currently, mainstream membrane materials are composite materials, typically consisting of a base layer, a coating, and a surface treatment layer.

PVDF Membrane

This is currently the most widely used and cost-effective membrane material. It is a composite material composed of a polyester fiber base coated with polyvinylidene fluoride (PVDF) resin.

Advantages

Strong Self-Cleaning Properties: The PVDF coating has a low absorption capacity for dust and contaminants, allowing it to be washed clean by rainwater.

Flexibility: Easy to process and tension, allowing for complex shapes.

Cost-Effective: More affordable than other high-end membrane materials.

Weather Resistance: Resists UV rays, wind and rain, and typically has a service life of 10-15 years. Suitable for budget-sensitive projects requiring balanced performance, such as stadiums, exhibition centers, industrial warehouses, and environmental cladding.

PTFE Membrane

This membrane is synonymous with "high performance." It consists of an ultra-fine glass fiber fabric base coated with polytetrafluoroethylene (commonly known as "Teflon").

Advantages

Excellent Durability: Exceptional weather resistance, aging resistance, and chemical stability, with a service life of over 25 years.

High Fire Rating: A Class A non-combustible material, offering excellent safety.

Excellent Self-Cleaning: The surface is extremely smooth, resists sticking to any substance, and remains white year-round.

Disadvantages: Expensive, slightly rigid, and requires high transportation and installation requirements.

Suitable for: Large stadiums (such as the exterior of the "Water Cube"), airport terminals, conference centers, and other permanent, landmark structures.

ETFE Membrane

ETFE is typically not a fabric, but rather a transparent fluoroplastic film. It is often used in the form of air pillows (such as the National Aquatics Center "Water Cube"). 

Advantages

Excellent light transmittance: It can reach up to 95%, comparable to glass, creating a bright indoor environment.

Lightweight and high-strength: It weighs only 1% of glass of the same area, yet offers exceptional toughness.

Superior weather resistance: It boasts a service life exceeding 25 years, an exceptionally smooth surface, and strong self-cleaning capabilities.

Energy-friendly and energy-saving: Shading and thermal performance can be controlled by adjusting the number of air cushion layers and the printed pattern.

Disadvantages: It is very expensive, and as an air cushion structure, it requires a continuous inflation system to maintain its shape.

Applications: Botanical gardens, swimming pools, commercial atriums, stadiums, and other areas requiring high light transmittance.

How to choose the right material?

Choosing the right material for an inflatable membrane structure is a complex process:

Budget consideration: PVDF is a cost-effective option, while PTFE and ETFE are for the high-end market.

Function consideration: Choose ETFE for high light transmittance; choose PTFE for durability and fire safety; PVDF is sufficient for general applications. Consider lifespan: Temporary structures can prioritize cost-effectiveness, while permanent structures should invest in long-lasting materials like PTFE.

Design: Complex hyperbolic shapes may require higher flexibility from the membrane material.