Since 1951, when the shape memory effect was first conclusively observed in alloys, shape memory materials have attracted great interest in the field of materials science. Shape memory materials are classified by their ability to be deformed and fixed into a given shape which reverts back to its original and permanent form after application of a thermal or optical stimulus. Shape memory polymers have grown in interest since the 1980s due to their ease of processing, low density and cheap cost compared to that of shape memory alloys. It can be shown that the elastomeric structure, amorphous chains held together by localized cross-links, of shape memory polymers can be further classified into four classes of thermally switchable shape memory polymers. A review of the chemistry and properties of the chemically and physically cross-linked matrices with switchable segments possessing Ttran=Tg or Ttran=Tm will be discussed. In addition liquid crystal elastomers will be touched upon as a fifth class of thermally induced shape memory polymers in which Ttran=TODT. The benefits of fillers in shape memory polymers as an indirect means towards thermal activation of the shape memory effect and optically induced shape memory due to azo and cinnamic groups  will also be discussed.


[loc]Hill conference [/loc]