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Controlling the Actuation Rate of Low-Density Shape-Memory Polymer Foams in Water
Pooja Singhal1, Anthony Boyle1, Marilyn L Brooks2
1Department of Biomedical Engineering, 5045 Emerging Technologies Building, 3120 TAMU, College Station, TX-77843, USA.
Abstract:
SMPs have been shown to actuate below their dry glass transition temperatures in the presence of moisture due to plasticization. This behavior has been proposed as a self-actuating mechanism of SMPs in water/physiological media. However, control over the SMP actuation rate, a critical factor for in vivo transcatheter device delivery applications, has not been previously reported. Here, a series of polyurethane SMPs with systematically varied hydrophobicity is described that permits control of the time for their complete shape recovery in water from under 2 min to more than 24 h. This control over the SMP actuation rate can potentially provide significant improvement in their delivery under conditions, which may expose them to high-moisture environments prior to actuation.
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