Wearable e-textiles are able to perform electronic functions and are perceived as a way to add features into common wearable textiles, building competitive market advantages. The e-textile production has become not only a research effort but also an industrial production challenge. It is important to know how to use existing industrial processes or to develop new ones that are able to scale up production, ensuring the behavior and performance of prototypes. Despite the technical challenges, there are already some examples of wearable e-textiles where sensors, actuators, and production techniques were used to seamlessly embed electronic features into traditional wearable textiles, which allow for daily use without a bionic stigma.

A wearable sensing glove for monitoring hand gestures and posture has been developed. The glove sensing capability is based on optical fiber Bragg gratings (FBGs) sensors. These sensors, due to their inherent self-referencing and multiplexing capability, are a value-added choice for this application. A single optical fiber would cross all the hand with Bragg structures in specific spots, as the finger joints. The functionality and performance of the glove was fully evaluated. The sensor response was linear to the hand movements for opening and closing down. Through the sensor response, it was possible to retrieve information about the joint angles from which other set of information like finger force can be estimated. The developed glove was able to provide numerical data about the angles of the hand posture in real time. The simplicity of the system and performance makes it well suitable for physical therapy applications, study of the human kinematics during sport activity, virtual reality or even remote control applications, among others.

Purpose: An issue when printing multi-material objects is understanding how different materials will perform together, especially because interfaces between them are always created. This paper aims to address this interface from a mechanical perspective and evaluates how it should be designed for a better mechanical performance. Design/methodology/approach: Different interface mechanisms were considered, namely, microscopic interfaces that are based on chemical bonding and were represented with a U-shape interface; a macroscopic interface characterized by a mechanical interlocking mechanism, represented by a T-shape interface; and a mesoscopic interface that sits between other interface systems and that was represented by a dovetail shape geometry. All these different interfaces were tested in two different material sets, namely, poly (lactic acid)–poly (lactic acid) and poly (lactic acid)–thermoplastic polyurethane material pairs. These two sets represent high- and low-compatibility materials sets, respectively. Findings: The results showed, despite the materials’ compatibility level, multi-material objects will have a better mechanical performance through a macroscopic interface, as it is based on a mechanical interlocking system, of which performance cannot be achieved by a simple face-to-face interface even when considering the same material. Originality/value: The paper investigates the importance of interface design in multi-material 3D prints by fused filament fabrication. Especially, for parts intended to be subjected to mechanical efforts, simple face-to-face interfaces are not sufficient and more robust and macroscopic-based interface geometries (based on mechanical interlocking systems) are advised. Moreover, such interfaces do not raise esthetic problems because of their working principle; the 3D printing technology can hide the interface geometries, if required.