Flexible Cyclic‐Poly(phthalaldehyde)/Poly(ε‐caprolactone) Blend Fibers with Fast Daylight‐Triggered Transience

Abstract

Cyclic‐poly(phthalaldehyde) (cPPHA) exhibits photo‐triggerable depolymerization on‐demand for applications like the photolithography of microfabricated electronics. However, cPPHA is inherently brittle and thermally sensitive; both of these properties limit its usefulness as an engineering plastic. Prior to this report, small molecule plasticizers are added to cPPHA‐based films to make the polymer more flexible. But plasticizers can eventually leach out of cPPHA, then leaving it increasingly more brittle throughout product lifetime. In this research, a new approach to fabricating flexible cPPHA blends for use as spun fibers is achieved through the incorporation of poly (ε‐caprolactone) (PCL) by a modified wet spinning method. Among blend compositions, the 50/50 cPPHA/PCL fiber shows fast transience (<50 s) in response to daylight while retaining the flexibility of PCL and mechanical properties of an elastomer (i.e., tensile strength of ≈8 MPa, Young's modulus of ≈118 MPa, and elongation at break of ≈190%). Embedding 2 wt% gold nanoparticles to cPPHA can further improve the transience rate of fibers comprising less than 50% cPPHA. These flexible, daylight‐triggerable cPPHA/PCL fibers can be applied to an extensive range of applications, such as wearable electronics, intelligent textiles, and zero waste packaging for which modest mechanical performance and fast transience are desired.

Controlling Polymeric Supramolecular Microstructures through Host–Guest Interactions Assisted with Ultrasound Oscillation

“…The band at 1157 cm –1 (Figure c) is identified as the amorphous conformation of PCL, and the band at 1294 cm –1 is due to crystallized PCL chains. ,, Since the guest PCL can be considered as an amorphous state when included in urea canals, the crystallinity indexes of PCL (ratios of band intensities at 1294 cm –1 and 1156 cm –1 ) were calculated and compared among IC samples. As shown in Table , the ratios of SM-ICs are all around 1.5, which are significantly lower than the value of the CM-IC, indicating that the ultrasound conditions may be beneficial for forming inclusion structures.…”

Composites of functional polymers: Toward physical intelligence using flexible and soft materials

“…Pyrene was included in the matrix as a photoabsorber, and a photoacid generator was included to facilitate depolymerization. In sunlight, these fibers disintegrated within 50 s [123]. When considering transient electronics, all components may need to be completely disintegrable.…”