4D Printing of Electroactive Triple-Shape Composites

• Published in: Polymers Vol. 15; no. 4; p. 832
• Main Authors: Razzaq, Muhammad Yasar, Gonzalez-Gutierrez, Joamin, Farhan, Muhammad, Das, Rohan, Ruch, David, Westermann, Stephan, Schmidt, Daniel F
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 07.02.2023; MDPI
• Subjects: 3D printing; 4D printing; Actuation; additive manufacturing; Automation; Carbon; Composite materials; electro-active composites; Fused deposition modeling; Glass transition temperature; Heat; Manufacturing engineering; Melting points; Morphology; Multi wall carbon nanotubes; Nanoparticles; Polyesterurethane; Polylactic acid; Polymer blends; Polymer matrix composites; Printing; Robotics; Scanning electron microscopy; Shape effects; Shape memory; shape-memory polymers; Smart materials; Temperature; Textiles; Thermal analysis; Three dimensional models; Three dimensional printing; Transmission electron microscopy; triple-shape effect; Germany; shape-memory polymers; electro-active composites; additive manufacturing; 4D printing; triple-shape effect
• ISSN: 2073-4360; 2073-4360
• DOI: 10.3390/polym15040832

Triple-shape polymers can memorize two independent shapes during a controlled recovery process. This work reports the 4D printing of electro-active triple-shape composites based on thermoplastic blends. Composite blends comprising polyester urethane (PEU), polylactic acid (PLA), and multiwall carbon nanotubes (MWCNTs) as conductive fillers were prepared by conventional melt processing methods. Morphological analysis of the composites revealed a phase separated morphology with aggregates of MWCNTs uniformly dispersed in the blend. Thermal analysis showed two different transition temperatures based on the melting point of the crystallizable switching domain of the PEU ( ~50 ± 1 °C) and the glass transition temperature of amorphous PLA ( ~61 ± 1 °C). The composites were suitable for 3D printing by fused filament fabrication (FFF). 3D models based on single or multiple materials were printed to demonstrate and quantify the triple-shape effect. The resulting parts were subjected to resistive heating by passing electric current at different voltages. The printed demonstrators were programmed by a thermo-mechanical programming procedure and the triple-shape effect was realized by increasing the voltage in a stepwise fashion. The 3D printing of such electroactive composites paves the way for more complex shapes with defined geometries and novel methods for triggering shape memory, with potential applications in space, robotics, and actuation technologies.