Li Shanshan, Rizvi Mehedi H, Lynch Brian B, Tracy Joseph B, Ford Ericka
Department of Textile Engineering, Chemistry and Science, North Carolina State University, 1020 Main Campus Drive, Raleigh, NC, 27695, USA.
Department of Materials Science and Engineering, North Carolina State University, 911 Partners Way, Raleigh, NC, 27695, USA.
Macromol Rapid Commun. 2021 Apr;42(7):e2000657. doi: 10.1002/marc.202000657. Epub 2020 Dec 28.
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.
环状聚邻苯二甲醛（cPPHA）具有光触发按需解聚的特性，适用于微纳电子光刻等应用。然而，cPPHA本质上易碎且对热敏感；这两个特性限制了它作为工程塑料的用途。在本报告之前，小分子增塑剂被添加到基于cPPHA的薄膜中，以使聚合物更具柔韧性。但是增塑剂最终会从cPPHA中渗出，从而使它在产品整个使用周期中越来越脆。在这项研究中，通过改良的湿法纺丝方法加入聚（ε-己内酯）（PCL），实现了一种制备用作纺丝纤维的柔性cPPHA共混物的新方法。在共混物组成中，50/50的cPPHA/PCL纤维在日光照射下显示出快速瞬变（<50秒），同时保留了PCL的柔韧性和弹性体的机械性能（即拉伸强度约为8MPa，杨氏模量约为118MPa，断裂伸长率约为190%）。向cPPHA中嵌入2wt%的金纳米颗粒可以进一步提高cPPHA含量低于50%的纤维的瞬变速率。这些柔性的、日光触发的cPPHA/PCL纤维可应用于广泛的领域，如可穿戴电子产品、智能纺织品以及对机械性能要求不高且需要快速瞬变的零废弃包装。
