Abstract
Wearable devices benefit from the use of stretchable conjugated polymers (CPs). Traditionally, the design of stretchable CPs is based on the assumption that a low elastic modulus (E) is crucial for achieving high stretchability. However, this research, which analyzes the mechanical properties of 65 CP thin films, challenges this notion. It is discovered that softness alone does not determine stretchability; rather, it is the degree of entanglement that is critical. This means that rigid CPs can also exhibit high stretchability, contradicting conventional wisdom. To inverstigate further, the mechanical behavior, electrical properties, and deformation mechanism of two model CPs: a glassy poly(3-butylthiophene-2,5-diyl) (P3BT) with an E of 2.2 GPa and a viscoelastic poly(3-octylthiophene-2,5-diyl) (P3OT) with an E of 86 MPa, are studied. Ex situ transmission X-ray scattering and polarized UV–vis spectroscopy revealed that only the initial strain (i.e., <20%) exhibits different chain alignment mechanisms between two polymers, while both rigid and soft P3ATs showed similarly behavior at larger strains. By challenging the conventional design metric of low E for high stretchability and highlighting the importance of entanglement, it is hoped to broaden the range of CPs available for use in wearable devices.
| Original language | English |
|---|---|
| Article number | 2306576 |
| Journal | Advanced Functional Materials |
| Volume | 33 |
| Issue number | 50 |
| DOIs | |
| State | Published - Dec 8 2023 |
Funding
Y.W. and S.Z. contributed equally to this work. Y.W. and X.G. thanks the financial aid from NSF grant DMR‐2047689 for supporting the majority of this work, particularly the mechanical characterization. Y.W. was supported in part by an ALS Doctoral Fellowship in Residence. Z.C. and X.G. thank the Department of Energy for supporting the X‐ray scattering of this work under grant number DE‐SC0022050. This research used resources beamline 12‐ID of the National Synchrotron Light Source II, a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Brookhaven National Laboratory under Contract No. DE‐SC0012704. The authors thank Mikhail Zhernenkov (NSLS‐II) for his assistance at the beamline and for the helpful discussions. S.Z. thanks NSF OIA‐1757220 for supporting his work. Z.L. and W.X. acknowledge the support from NSF OIA‐2119691 (AI‐SUSTEIN). Access to the CCAST supercomputing capability at NDSU is also acknowledged for molecular modeling. K.‐L.C. and Y.‐C.C. thank the financial support from the National Science and Technology Council in Taiwan (NSTC 111‐2628‐E‐011‐008‐MY3) for supporting device fabrication and testing. A portion of morphology characterization was done at the Molecular Foundry, which is supported by the Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract No. DE‐AC02‐05CH11231. Y.W. and S.Z. contributed equally to this work. Y.W. and X.G. thanks the financial aid from NSF grant DMR-2047689 for supporting the majority of this work, particularly the mechanical characterization. Y.W. was supported in part by an ALS Doctoral Fellowship in Residence. Z.C. and X.G. thank the Department of Energy for supporting the X-ray scattering of this work under grant number DE-SC0022050. This research used resources beamline 12-ID of the National Synchrotron Light Source II, a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Brookhaven National Laboratory under Contract No. DE-SC0012704. The authors thank Mikhail Zhernenkov (NSLS-II) for his assistance at the beamline and for the helpful discussions. S.Z. thanks NSF OIA-1757220 for supporting his work. Z.L. and W.X. acknowledge the support from NSF OIA-2119691 (AI-SUSTEIN). Access to the CCAST supercomputing capability at NDSU is also acknowledged for molecular modeling. K.-L.C. and Y.-C.C. thank the financial support from the National Science and Technology Council in Taiwan (NSTC 111-2628-E-011-008-MY3) for supporting device fabrication and testing. A portion of morphology characterization was done at the Molecular Foundry, which is supported by the Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
Keywords
- chain alignment mechanism
- deformable rigid glassy conjugated polymers
- mechanical properties of conjugated polymer thin films