Shape Memory Elastomers
Patrick T. Mather Syracuse Biomaterials Institute and Biomedical and Chemical Engineering Department Syracuse University
Host: Mark Bowick | Contact: Yudaisy Salomon Sargenton, firstname.lastname@example.org
Shape memory polymers (SMPs) constitute a unique class of polymers that have the ability to fix a temporary shape until they are triggered to return to their original form by an external stimulus. The shape changing mechanism is performed around a transition temperature, often a glass transition temperature (Tg), and relies on vitrification of the chains upon cooling to fix the temporary shape. As a result, SMPs in their fixed state are relatively stiff. A need exists for soft, extensible SMPs with mechanical properties that more closely match those of human tissue. Our group has previously introduced a shape memory elastomeric composite (SMEC) that is rubbery and soft, and yet, has the ability to fix a temporary shape. There, processing approach of imbibing a fiber preform with a silicone precursor was both time-consuming and compositionally restrictive. The work we will present introduces a comparatively simple strategy to prepare SMECs more efficiently and with more control over the composition, thus allowing for adjustment of material properties to meet requirements of a variety of applications. Two polymers are simultaneously electrospun, or dual-spun, forming a composite fiber mat with a controllable composition. This process is shown in the accompanying figure. The two polymers were chosen such that one assists in ‘shape fixing’ and the other in ‘shape recovery’. We will report on the quantitative physical characterization of the new materials, including shape memory properties, also shown in the figure. Finally, very recent work on a reconfigurable shape memory composite will be introduced, with reconfiguration being enabled by anhydride exchange between network chains. We envision that the versatility and simplicity of this fabrication approach will allow for large scale production of shape memory elastomeric composites (SMECs) for a wide range of applications.