In developing advanced materials for adaptive structures and flexible electronics, we have previously reported* origami-inspired polyimides and fabrication to create permanent 3D-shapes using crosslinked poly(amic acid)s, which upon imidization provided recoverable shape-memory behavior. In broadening our effort to develop high temperature shape-memory materials, new lower-temperature in-situ phenylethynyl(PE) crosslinking chemistry was applied. Using novel PE dianhydrides and commercially available diamine (APB) and dianhydride (6FDA), the amic-acid and imide copolymers are crosslinked via the PE groups at temperatures near their Tg‘s. Utilizing PE crosslinking near the initial Tg, 3D objects with predetermined shapes are fabricated from these copolymers using our origami-inspired processing scheme. This method allows for the unique capability of assuming 2D or any other temporary shapes under applied stress near the Tg and maintaining this temporary shape at room temperature and without applied stress. When exposed to temperatures near the Tg, the object's temporary shape will recover to the predetermined 3D shape. Incorporation of these novel PE reactive groups allows for crosslinking to occur near the initial Tg, which increases the mechanical properties of the resulting polymer. These crosslinked polyimides exhibit flexible and creasable behavior with 100% shape-memory recovery and 99% shape-memory fixity over many stress-strain-temperature cycles.

In-situ phenylethynyl crosslinking of polyimides for shape-momory objects

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ACS Fall 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.