Cold hibernated elastic memory

More sophisticated versions of SMPs are those based on the so-called cold hibernated elastic memory as self-deployable intelligent structures (Sendijarevic, 2003). This technology is based on polyurethane foams whereby shape memory effect is combined with elastic recovery of the foam, thus allowing them to be packed into the smallest possible form and inserted into the body via catheters. Given the foam s excellent biocompatibility, porosity, and lightness, they can potentially be used in many other forms, e.g., orthopaedic braces and splints, vascular and coronary crafts, as well as other equally vital prosthetics and implants. 

Metcalfe, A., Desfaits, A.-C., Salazkin, I., Yahia, L. H., Sokolowski, W. M. Raymond, J. (2003) Cold hibernated elastic memory foams for endovascular interventions. Biomaterials, 24, 491—497. 

Recently, the concept of cold hibernated elastic memory utilising SMP in open cellular structures was proposed for space-bound structural applications [108]. The concept of cold-hibernated elastic memory can be extended to various new applications such as microfoldable vehicles, shape determination and microtags [109]. Recent studies on shape memory PU-based conductive composites using conducting polymers and carbon nanotubes show considerable promise for application as electroactive and remote sensing actuators [110]. 

In 2003, Metcalfe et al. reported on using polyurethane SMP foams, termed CHEM (cold hibernated elastic memory) foams, for treating carotid aneurysms in a... 

Sokolowski, W, 2005. Potential bio-medical and commercial applications of cold hibernated elastic memory (CHEM) self-deployable foam structures. Smart Materials HI 5648, 397 05. 

Metcalfe et al. (2003) tested cold hibernated elastic memory (CHEM) polyurethane for the treatment of lateral wall aneurysms on the carotid arteries of dogs. The SMP polyurethane was made in open cellular (foamy) structures with the glass transition temperature of 60 C. After 3 weeks, in vivo experiments showed that the CHEM foam led to improved aneurysm embolization, and a thick neoin-tima formation by favoring the ingrowth of cells. However, residual necks and recurrences were observed in some cases due to the incomplete filling of the vascular lumen. 

Sokolowski, W. (2004) Cold hibernated elastic memory self-deployable and rigidizable structure and method therefore. US Patent 6,702,976 B2, Mar. 9, 2004. 

---