All-Organic Electroactive Shape-Changing Knitted Textiles Using Thermoprogrammed Shape-Memory Fibers Spun by 3D Printing

Abstract

Here, we present knittable shape-memory polymeric fibers extruded using a 3D-printer nozzle-based melt-spinning method for high throughput of composition and condition testing. These structures are used as the basis for electroactive shape-changing knitted textiles combining several types of fibers, including organic fibrous heaters. These structures represent a different approach to “on-demand” shape-memory fibers and can be incorporated into a variety of textile architectures, including inlaid knitting, diagonal interlacements, and a knit/purl design for an anisotropic knitted texture. The influence of manufacturing process parameters (e.g., drawing ratio during melt-spinning) on physical properties of the shape-memory fibers was measured using X-ray diffraction, thermomechanical cycling, scanning electron microscopy, and mechanical testing. The degree of crystallinity increased from 19.4 to 22.4% with the increased drawing ratio, with a maximum strain % of 450 and the fibers being able to lift 457 times their own weight. Further, we present a scalable strategy for bicomponent filament production, in which two distinct polymers are melt-spun in a side-by-side configuration and when actuated showed a coiled structure with different mechanical and thermal behavior than pure SMP fibers. The knitted textiles, obtained with a computer-controlled knitting machine able to produce 3D knitted structures, are deformed from two-dimensional planar structures to three-dimensional conformations by applying a voltage to the organic fibrous heaters. The deformed structure can be fixed by removing the applied voltage and can be returned to a planar configuration by heating and applying an uniaxial stress. Therefore, a hierarchical approach for fully textile-based, bendable, knittable, and electroactive soft actuators is presented. The results presented here demonstrate lab-scale production and high-throughput screening of advanced fibers with tunable properties.

Soft Fiber/Textile Actuators: From Design Strategies to Diverse Applications

“…As key components, textile-based actuators have been used in many wearable devices, such as devices to assist human movement, and smart clothing for regulating human comfort. Textile actuator implementation typically occurs in two ways: one is sewing stimulus-responsive fibers into everyday textiles, , and the other is weaving or knitting fiber actuators directly into fabrics . As examples, Figure a demonstrates how active liquid crystal elastomer (LCE) yarns, combined with conventional textile yarns, produce textiles capable of contract/relax and 3D deformations …”

A decorating 3D Printing on cotton T-shirt utilizing fused deposited soft TPU material

“…Printing on textile fabric is strongly related with parameters of 3D printer and textile used as base substrate [19,20]. Despite created for aesthetic [21] or functional purpose [22,23], one of the main problems encountered with the composite structure is adhesion between textile fabric and 3D printed material [24,25]. From the literature surveyed there is a high number of papers published dealing with test of adhesion of printed material on textile fabrics [26].…”

Design and Synthesis of Shape Memory Phenol-Formaldehyde with Good Irradiation Resistance, Thermal, and Mechanical Properties

“…The temporary shape can be maintained for a long time by cooling down below T trans and then the permanent shape can be automatically recovered upon reheating above T trans . Recently, SMPs and their composites have been applied in many fields including aerospace, − biomedicine, textiles, − and electron devices. − So far, SMPs including polyurethane (PU), − cyanate, , epoxy, − polylactic acid, polyimide, , polyaryletherketone, and rubber , have been reported. However, the study of shape memory phenol-formaldehyde (SMPF) resin is rarely reported. , …”