Published Sep 10, 2013

Guoguang Niu  


The term "shape memory effect" refers to the ability of a material to be deformed and fixed into a temporary shape, and to recover its original, permanent shape upon an external stimulus (1). Shape memory polymers have attracted much interest because of their unique properties, and applied tremendously in medical area, such as biodegradable sutures, actuators, catheters and smart stents (2, 3). Shape memory usually is a thermally induced process, although it can be activated by light illumination, electrical current, magnetic, or electromagnetic field (4-6). During the process, the materials are heated directly or indirectly above their glass transition temperature (Tg) or the melting temperature (Tm) in order to recover the original shape. Non-thermally induced shape memory polymers eliminate the temperature constrains and enable the manipulation of the shape recovered under ambient temperature (7, 8). Herein, we report a novel strategy of water induced shape memory, in which the formation and dissolution of poly(ethylene glycol) (PEG) crystal is utilized for the fixation and recovery of temporary deformation of hydrophilic polymer. This water-induced shape recovery is less sensitive to temperature, of which 95% deformation is fixed in circumstance and over 75% recovery is reached even at 0 oC.



Shape Memory, Biodegradable, Biomaterials, Poly(Ethylene Glycol), Crystal

1. Osada Y, Matsuda A. Shape memory in hydrogels. Nature 1995; 376: 219.

2. Lendlein A, Langer R. Biodegradable elastic shape-memory polymers for potential biomedical applications. Science 2002; 296: 1673-6.

3. Gall K, Yakacki CM, Liu Y, Shandas R, Willett N, Anseth KS. Thermomechanics of the shape memory effect in polymers for biomedical applications. J Biomed Mater Res Part A 2005; 73: 339-48.

4. Koerner H, Price G, Pearce NA, Alexander M, Vaia RA. Remotely actuated polymer nanocomposites-stress-recovery of carbon-nanotube-filled thermoplastic elastomers. Nat Mater 2004; 3: 115-20.

5. Vaia R. Nanocomposites: remote-controlled actuators. Nat Mater 2005; 4: 429-30.

6. Razzaq MY, Anhalt M, Frormann L, Weidenfeller B. Thermal electrical and magnetic studies of magnetite filled polyurethane shape memory polymers. Mater Sci Eng A 2007; 444: 227-35.

7. Palffy-Muhoray P, Camancho-Lopez M, Finkelmann H, Shelley M. Fast liquid crystal elastomer swins into the dark. Nat Mater 2004; 3: 307-10.

8. Gupta MC and Deshmukh VG. Thermal oxidative degradation of poly-lactic acid Part II: molecular weight and electronic spectra during isothermal heating. Colloid & Polymer Sci 1982; 260: 514-7.

9. Huang WM, Yang B. Water-driven programmable polyurethane shape memory polymer: demonstration and mechanism. Applied Physics Letter 2005; 86: 114105.

10. Yang B, Huang WM, Li C, Li L. Effects of moisture on the thermomechanical properties of a polyurethane shape memory polymer. Polymer 2006; 47: 1348-56.
How to Cite
Niu, G. (2013). Water Triggered Shape Memory Materials. Science Insights, 3(1), 49–50. https://doi.org/10.15354/si.13.rp010