An Enabling Strategy for Developing Triple Shape Memory Polymers with a Broad Glass Transition Temperature Range via Melt Blending of Miscible Hard‐Soft Polymers

ABSTRACT

Triple shape memory polymers (TSMPs) enable sequential shape transformations for deployable and biomedical devices, yet their development often requires complex synthesis/chemical crosslinking and/or processing. Here, the scalable melt‐blending strategy of commercially available hard‐soft polymers enables thermoplastic TSMPs, exhibiting microscale miscibility and molecular relaxation induced by self‐concentration at the segmental‐scale. Binary PMMA/PVDF and PC/PCL blends, together with ternary PMMA/PVDF/PEO systems, demonstrate miscibility, evidenced by a single glass transition, broad molecular relaxation spectra, and the absence of distinct amorphous polymer‐rich phases. Dynamic mechanical thermal analysis reveals substantial glass transition broadening, reaching ≈45 °C in PMMA/PVDF/PEO and ≈70 °C in PC/PCL blends, thereby providing thermal actuation windows for programmable triple shape memory behavior. All systems demonstrate high shape fixity and shape recovery ratios, while PC/PCL blends generate actuation stresses up to 8.04 MPa. The best‐performing compositions maintain stable shape and stress recovery over three successive cycles. Their broad thermal working windows, strong actuation capability, and thermoplastic processability enable versatile multi‐stage actuation. Stress recovery analysis indicates that self‐tightening TSMP staples may potentially provide staged wound closure to reduce tissue stress concentrations associated with conventional single‐step closure. This work establishes a practical route toward high‐performance thermoplastic TSMPs for engineering and biomedical applications.