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Fig. 107 Memory polymer film between two textile layers (Source: Techtextil Symposium 1999)
A prototype was made using a bi-material laminated film consisting of a layer of shape memory
polymer (with a glass transition temperature of 25°C) film and a layer of a compatible elastomeric film.
When the temperature drops below 25°C the shape memory layer will shrink linearly by some 3 % and
become rigid, creating an out-of-plane deformation. It is anticipated that the deformed laminated films
will provide reversible enhanced thermal insulation in response to cold.
When using a shape memory polymer with a glass transition temperature in the region of 55°C a
laminate could be formed to protect against heat.
A few remarkable achievements have been made in water vapour permeable materials where,
through the use of shape memory polymers, a water vapour permeation rate is achieved controlled by
the difference in relative humidity and temperature. Casual and sportswear clothing have been
developed which keep the wearer warm in cold season and cool in hot season. Examples can be
found in the subsequent paragraphs.
Mitsubishi Heavy Industries introduced the polyurethane membrane ‘DiAPLEX-The intelligent material’
to the outer wear market, which is waterproofed, windproofed and breathable. Its functionality is based
on the principle of thermal vibrations. The shape memory polymer can be attached in form of a
laminate to a variety of fabrics, being capable to adapt to the surrounding environmental conditions.
Fig. 108 Cross-section of a fabric with a DiAPLEX membrane [189]
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