material that can be manipulated and deformed only to return to its original
shape as necessary.
This invention relates to a class of network polymers,
containing reversibly associating side-groups that can be structurally tailored
as ?shape memory? materials for a variety of applications in biotechnology and
medicine as well as such other uses as shapeable tools, intelligent packaging,
recyclable thermosets, etc. They contain both covalent and non-covalent
cross-links and can readily be deformed to over 100% strain and be tailored to
return to their original shape on a desired timescale. They are solid,
transparent, soft and comfortable to touch.
invention describes a class of shape memory polymers whose properties can be
tailored to specific applications. They are typically made up of three
constituents: hydrogen-bonding units, cross-linking units and backbone modifying
units. When elastically strained, they form non-covalent bonds through
their self-complimentary side-groups which on lowering temperature, can hold or
?pin? the material in the strained shape. Since the association of
side-groups is a completely reversible process, the material will eventually
relax to its original state. The rate of strain relaxation is influenced by the
number and type of covalent cross-links, non-covalent hydrogen bonds, and
temperature. These materials differ from traditional shape memory
materials because they are transparent and rubber in their low-temperature,
strained state. The materials are easy to prepare and can readily be processed
and fabricated to the desired size and shape.