Actuators have wide applications in intelligent robots, deformable textiles, and wearable devices, wherein the fiber‐based coiled linear actuators are particularly advantageous due to their good flexibility, high stress, and strain. However, their performances have been limited by the employed materials, whose microstructures are not easily designed and controlled. This article proposes a new approach of engineered composite yarns for the actuators. It leads to novel solutions to overcome these difficulties by offering wide design options in material properties and device structures. Here, an engineering design of programmable and thermally‐hardening helical composite yarn actuators (HCYAs) with a wide range of operating temperature is exemplified. Polyimide (PI) and polydimethylsiloxane (PDMS) are selected to fabricate HCYAs, achieving tensile actuation of 20.7% under 1.2 MPa from −50 °C to 160 °C and competitive specific work (158.9 J kg‐1, four times of natural muscle). With constant tensile deformation, PI/PDMS HCYA nearly tripled the stress from 20 °C to 100 °C. Moreover, it is surprisingly observed an unusual thermal‐hardening phenomenon that the tensile stiffness of the PI/PDMS HCYAs increases with the rise of temperature. Equipped by electrothermally powered PI/Cu/PDMS HCYAs, robotic hands and pressure‐tunable compressive bandage are demonstrated for their potential applications in robots and wearable devices.

This paper reports a comparative experimental study of single jersey knitted fabrics made from a novel bio-based and degradable polylactide acid/poly (hydroxybutyrate-co-hydroxyvalerate) (PLA/PHBV) multi-filament yarn, together with polylactide acid , Cupro, polyethylene terephthalate (PET) and polyamide 6 (PA 6) multi-filament yarns. Their structures, mechanical, thermal and surface properties and performances as well as anti-bacterial behavior are measured and compared. It has been found that the polylactide acid/poly (hydroxybutyrate-co-hydroxyvalerate) (PLA/PHBV) filament yarn has adequate thermal and mechanical properties for normal textile and coloration/finishing processes. The Young's modulus of polylactide acid/poly (hydroxybutyrate-co-hydroxyvalerate) (PLA/PHBV) multi-filament yarn is the lowest among all the candidates investigated except for polyamide 6 (PA 6). The dyed polylactide acid/poly (hydroxybutyrate-co-hydroxyvalerate) (PLA/PHBV) fabric has the highest softness rating among all the fabrics. Single jersey knitted fabrics from the polylactide acid/poly (hydroxybutyrate-co-hydroxyvalerate) (PLA/PHBV) filament yarn have a bursting strength, extension and recovery that satisfy the industrial requirement. In addition, after fully relaxation, the dyed polylactide acid/poly (hydroxybutyrate-co-hydroxyvalerate) (PLA/PHBV) knitted fabrics exhibit an outstanding pilling resistance, favorable snagging property, as well as good air permeability, Qmax and smoother surface. Finally, this study has led to a discovery of excellent anti-bacterial performance of 100% polylactide acid/poly (hydroxybutyrate-co-hydroxyvalerate) (PLA/PHBV) fabrics against staphylococcus aureus, klebsiella pneumoniae, candida albicans according to AATCC100-2012.

This paper reports an investigation of dyeing processes of textiles made from a novel 100% bio-based and fully degradable polylactide/poly (hydroxybutyrate-co-hydroxyvalerate) (PLA/PHBV) fiber. The dye exhaustion, depth of shade and fastness, as well as bursting strength of dyed PLA/PHBV fabrics have been evaluated in terms of types and concentration of dyestuff, dyeing bath temperature, duration, liquor ratio and pH value. Finally, the energy cost of the whole dyeing process of the proposed material is calculated and compared with that of polyethylene terephthalate. The experimental results show that an excellent dyeing effect and bursting strength can be achieved by properly applied dyes (e.g. C.I. Disperse Orange 30, Red 74, and Blue 79) under optimal low-dyeing-temperature conditions (100℃, 10 min, pH 5, LR 30:1). In addition, considering the low energy cost during the whole process, PLA/PHBV fibers can be regarded as a promising and environment-friendly material for the textile industry.

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Extended from our previous finding that poly (3-hydroxybutyrate) (PHB) oligomer is an effective antimicrobial agent against gram-positive bacteria, gram-negative bacteria, fungi and multi-drug resistant bacteria, this work investigates the effect of polyethylene glycol (PEG) on the antimicrobial effect of PHB oligomer. To investigate and explain this promoting phenomenon, three hypothetic mechanisms were proposed, that is, generation of new antimicrobial components, degradation of PHB macromolecules and dissolution/dispersion of PHB oligomer by PEG. With a series of systematic experiments and characterizations of high-performance liquid chromatography–mass spectrometry (HPLC-MS), it was deducted that PEG promotes the antimicrobial effect of PHB oligomer synergistically through dissolution/dispersion, owing to its amphipathy, which improves the hydrophilicity of PHB oligomer.