Facile Fabrication of Photochromic Poly(lactic acid)/poly(3-hydroxybutyrate-co-3-hydroxyvalerate)\nFibers via a Scalable Melt-Spinning Process

Abstract

Due\nto their green, low-carbon, and sustainable resource qualities,\nphotochromic poly(lactic acid) (PLA) fibers provide various advantages\nin the development of smart textiles, such as sensing and camouflage.\nHowever, the stiffness and rough texture of functional PLA fibers\ncan have an impact on textile comfort and restrict their application.\nIn our work, we used a scalable melt-spinning approach to create photochromic\nfibers with PLA and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV)\nas fiber-forming polymers and photochromic microcapsules as color\nindicators, respectively. When exposed to intense sunlight, photochromic\nPLA/PHBV fibers transform from colorless to blue in 1 s then back\nto colorless in 1 min when the activation irradiation is removed.\nThe tenacity and initial modulus of photochromic PLA/PHBV fibers decrease\nfrom 4.30 to 3.57 cN/dtex and 66.20 to 27.91 cN/dtex, respectively,\nas the PHBV component content increases from 0% to 20% wt %, suggesting\nacceptable tenacity and good flexibility. As the PHBV content increases,\nPHBV can nucleate PLA to promote the crystal growth rate of PLA, but\nit results in thinner or less perfect PLA lamellae and a more disordered\namorphous region in the photochromic PLA/PHBV fibers. This structure\nreduces the tenacity of photochromic PLA/PHBV fibers while enhancing\nsoftness.