4D Printed Shape Memory Polymers: Morphology and Fabrication of a Functional Antenna

Shape memory polymers (SMPs) are smart materials that can respond to certain thermal, chemical or electrical stimuli by inducing a structural conformation change into a temporary shape. In this work, a 3D printing process based on a Vat Photo-polymerization of a shape memory polymer (SMP) was investigated to produce customized smart and complex morphable antennas. The mechanical and material properties were examined through a tensile, flexural and rheological testing for different polymer mixture ratios. It was observed that the combination of 20% of an elastomeric resin in a thermoset UV system yields the highest shape recovery performance. The fabrication process of the antenna was based on the incorporation of a conductive material. The approach involved the inclusion of a thin copper electroplating technique. The radiofrequency performance of the fabricated antenna was examined by a vector network analyzer (VNA) and it was observed that a thermal stimulus was capable of inducing a conformal shape on the antenna, resulting in a multi-radio frequency morphing system. The antenna performance was simulated in Ansys HFSS.