Memory effects in polymers

Heuchel, M., Sauter, T., Kratz, K., and Lendlein, A. (2013) Thermally induced shape-memory effects in polymers quantification and related modeling approaches. Journal of Polymer Science Part B Polymer Physics, 51, 621-637. 

Gall, K., Yakacki, C.M., Liu, Y., Shandas, R., Willett, N., and Anseth, K.S. (2005) Thermomechanics of the shape memory effect in polymers for biomedical applications. Journal of Biomedical Materials Research Part A, 73, 339-348. 

Memory effects in polymer liquid crystals influence of thermal history of phase behavior... 

Ding, Z, PumawaU, H., Tang, C., and Zhang, J.L. (2012) Thermo/chemo-responsive shape memory effect in polymers a sketch of working mechanisms, fundamentals and optimization. /. Polym. Res., 19 (9), 1—34. 

Fig. 1 Stimmaiy of the mechanisms for the shape memory effect in polymer networks. Reprinted from Meng and Li [6], Copyright 2013, Open Access...

Thermal history, also known as heat history, describes the memory effect in polymers. In simple terms, polymers are affected by hot or cold temperatures and remember the last effect. This is considered a variable that should be controlled in the laboratory. Thermal history has a strong influence on the material s glass transition, melting, and crystallization temperatures. Temperature changes, both hot and cold temperatures, induce thermal stresses in the material. The extent and implication of thermal stresses to a polymer are usually unknown and uncontrolled. This variable may be of interest for those who want to know more about the sample as it was received in the laboratory or how it reacts to an uncontrolled end-use environment. Usually this is of interest, but because it is uncontrolled it is very difficult to rely on for material comparisons. 

Shape memory effect in polymers is normally achieved by relaxation of the polymeric chains due to changes in temperature.When the programming and recovery stages in the shape memory effect are produced by changes in temperature, it is said that the effect is thermally induced. 

Bending tests associated with thermal q cles are also able to characterize the shape memory effect in polymers (Knight et ah, 2009 Luo et al, 2008 Zheng et al, 2006,2008 Zhou et al, 2007). In the flexure test the measured quantity is the angle of deformation. The following coefficient is defined to quantify the ability of a material to recover its original shape ... 

Li, J., Viveros, J. A., Wme, M. H., Anthamatten, M. (2007), Shape-memory effects in polymer networks containing reversibly associating side-groups, Adv. Mater., 19, 2851-5. 

Shaojun Chen, Jinlian Hu, Haitao Zhuo, Yong Zhu. Two-way shape memory effect in polymer laminates. Materials Letters. Volume 62, Issue 25, 30 September 2008, Pages 4088 090. 

Alfonso GC, Scardigli P. Melt memory effects in polymer crystallization. Macromol Symp 1997 118 323-328. 

Lee JH, Lim TK, Kwon YW, Jin J (2005) Memory effects in polymer stabilized ferroelectric liquid crystals, and their dependence on the morphology of the constituent molecules. J Appl Phys 97 (8) 084907... 

The shape memory effect in polymers is based on a large difference in the glassy... 

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