Littérature scientifique sur le sujet « 3D Plastronics »

Harvesting of ambient radio-frequency energy is largely covered in the literature. The RF energy harvester is considered most of the time as a standalone board. There is an interest to add the RF harvesting function on an already-designed object. Polymer objects are considered here, manufactured through an additive process and the paper focuses on the rapid prototyping of the harvester using a plastronic approach. An array of four antennas is considered for circular polarization with high self-isolation. The RF circuit is obtained using an electroless copper metallization of the surface of a 3D substrate fabricated using stereolithography printing. The RF properties of the polymer resin are not optimal; thus, the interest of this work is to investigate the potential capabilities of such an implementation, particularly in terms of freedom of 3D design and ease of fabrication. The electromagnetic properties of the substrate are characterized over a band of 0.5–2.5 GHz applying the two-transmission-line method. A circular polarization antenna is experimented as a rapid prototyping vehicle and yields a gain of 1.26 dB. A lab-scale prototype of the rectifier and power management unit are experimented with discrete components. The cold start-up circuit accepts a minimum voltage of 180 mV. The main DC/DC converter operates under 1.4 V but is able to compensate losses for an input DC voltage as low as 100 mV (10 μW). The rectifier alone is capable of 3.5% efficiency at −30 dBm input RF power. The global system of circularly polarized antenna, rectifier, and voltage conversion features a global experimental efficiency of 14.7% at an input power of −13.5 dBm. The possible application of such results is discussed.

AbstractSuperhydrophobic surfaces are known to resist diatom and bacteria adhesion if stable air layers are formed underwater (known as a plastron). However, most preparation techniques to obtain superhydrophobic surfaces need sophisticated chemical treatments and/or complicated chemical procedures. Here a 3D printing technique is used to create different molds for polymer casting. A conductive graphite‐carbon black‐silicone composite mixture is developed to fabricate different polymer surface casts from these molds. The obtained surfaces exhibited contact angles >145°, which led to a plastron formation on the surfaces underwater, and areas with intact plastrons protected the samples from diatom attachment. Due to the conductivity of the coatings, it is possible to replenish the plastrons by heating the surfaces.

Cette thèse explore le domaine émergent de la plastronique 3D, qui fusionne l’électronique et la plasturgie pour intégrer des circuits électroniques sur des substrats 3D en polymère. Le travail se concentre sur le développement d’encres conductrices pour le procédé In-Mold Electronics (IME), une technique prometteuse pour la production en grand volume de dispositifs plastroniques, en particulier pour les interfaces homme-machine (IHM). Le processus IME comprend plusieurs étapes : l’impression de pistes conductrices sur un film mince de polycarbonate à l’aide d’encre conductrice, le transfert des composants électroniques sur le film et leur connexion au circuit par collage, le thermoformage du film en 3D et le surmoulage 3D par injection de thermoplastique. Après une revue de la littérature sur la plastronique et l’IME, la thèse propose l’étude de différentes formulations d’encres conductrices, en se concentrant sur celles composées d’une matrice polymérique organique contenant des charges d’argent micrométriques. Une méthodologie a été mise en place pour caractériser les encres à chaque étape du processus, en termes de résistivité électrique, d’adhésion, d’étirement et de cisaillement sous contraintes lors des étapes d’impression, de thermoformage et de surmoulage. Le polycarbonate a été utilisé comme matériau de référence pour le film et la matière de surmoulage. Plusieurs encres conductrices ont été élaborées à partir de matériaux organiques issus de la pétrochimie ou de matériaux biosourcés. À partir de matériaux pétrosourcés, nous avons obtenu des encres peu résistives (26 µΩ.cm) et avec une grande capacité de déformation par thermoformage. À partir de matériaux biosourcés, de nouvelles matrices organiques ont été formulées pour obtenir des encres plus responsables. Les encres -bio- se distinguent par leur respect de l’environnement grâce à un liant biodégradable, un solvant vert biosourcé et l’argent recyclable. Les performances atteignent une faible résistivité de 20 µΩ.cm et avec une grande capacité de déformation par thermoformage. Une encre -bio- a été surmoulée avec du polycarbonate, et un démonstrateur IME a été réalisé. Cependant, certaines difficultés persistent et limitent le potentiel d’application de ces formulations. Parmi elles, des cas critiques de délamination et de rupture des pistes conductrices lors du thermoformage. Également, de possible délavage des encres et le détachement des composants électroniques lors de l’étape d’injection peuvent survenir. Ces limitations sont liées aux contraintes géométriques engendrées par le 3D et ont été étudiées. Cependant, par contrainte de temps, toutes les encres n’ont pas pu être testées jusqu’à la réalisation d’un démonstrateur
This thesis explores the emerging field of 3D plastronics, which merges electronics and plastics engineering to integrate electronic circuits on 3D polymer substrates. The work focuses on the development of conductive inks for the In-Mold Electronics (IME) process, a promising technique for the high-volume production of plastronic devices, particularly for human-machine interfaces (HMIs). The IME process involves several steps: printing conductive tracks on a thin polycarbonate film using conductive ink, transferring the electronic components onto the film and connecting them to the circuit by bonding, thermoforming the film in 3D, and 3D overmolding by injection of thermoplastic. After a literature review on plastronics and IME, the thesis proposes the study of different formulations of conductive inks, focusing on those composed of an organic polymer matrix containing micrometric silver fillers. A methodology was set up to characterize the inks at each stage of the process, in terms of electrical resistivity, adhesion, stretching and shear under stress during the printing, thermoforming and overmolding stages. Polycarbonate was used as a reference material for the film and the overmolding material. Several conductive inks were developed from organic materials derived from petrochemicals or bio-based materials. From petro-based materials, we obtained low-resistivity inks (26 µΩ.cm) and with a high deformation capacity by thermoforming. From bio-based materials, new organic matrices were formulated to obtain more responsible inks. The -bio- inks are distinguished by their respect for the environment thanks to a biodegradable binder, a bio-based green solvent and recyclable silver. The performances reach a low resistivity of 20 µΩ.cm and with a high deformation capacity by thermoforming. A -bio- ink was overmolded with polycarbonate, and an IME demonstrator was produced. However, some difficulties persist and limit the application potential of these formulations. Among them, critical cases of delamination and rupture of the conductive tracks during thermoforming. Also, possible washing out of the inks and the detachment of the electronic components during the injection step can occur. These limitations are linked to the geometric constraints generated by 3D and have been studied. However, due to time constraints, not all the inks could be tested until the production of a demonstrator