Gregory Martin Treich

An all-organic fabric patch antenna is realized with the help of nanotemplates-assisted PEDOT:PSS conductive phase segregation, paving a new way for clothing integrated wearable electronic networks.

Enhancing dipole polarization has been demonstrated as an effective approach to increase the dielectric constant of polymer dielectrics and thus to improve their discharged energy density for energy storage applications in electrical power and electronic systems. However, further optimization to get a higher dielectric constant and lower polarization loss hinges upon a more insightful understanding of the dynamics of dipole relaxation. Here, we demonstrate an approach, based on the Dissado-Hill dielectric response model, to probe the dynamics of dipole polarization in an all organic polythiourea (PDTC-HK511) composed of p-phenylene diisothiocyanate (PDTC) as rigid segments and Jeffamine® HK511 as flexible segments. Our results reveal that PDTC-HK511 possesses strong subglass transition β and γ relaxation processes in conjunction with the quasi-DC diffusion process at relatively high temperature and a low frequency range. The γ relaxation enhances the dielectric constant by 20%–25% but causes no apparent loss at the operating temperature and frequency conditions due to the high flexibility and short relaxation time of the dipole orientation. In comparison to β relaxation, the weak interactions and much shorter relaxation time of dipoles in γ relaxation evidenced the large flexibility of dipole movement. This work provides deeper insight into the dipole movement and aids future rational designs of polymers for dielectric energy storage.

Advanced polymers with high energy density and high efficiency are urgently needed in pulse power capacitor applications. Here, we present a practical design approach towards all-organic polymers with high energy density and high efficiency by enhancing dipolar polarization at the molecular level. Flexible segments were introduced into the backbones of rigid polar aromatic polymers to increase the flexibility of dipoles. Dielectric spectroscopy measurements of designed polymers revealed multiple strong sub-glass transition (sub-T_g) relaxation peaks with low activation energies, which indicated the enhanced movement freedom of dipoles below the glass transition temperature. As a result, dielectric constants were increased up to 46% when compared with their base polymers and D–E loop measurements showed that all these designed polymers had high energy densities above 11 J cm⁻³ with efficiencies above 90%. These results unveiled a novel approach towards high dielectric constant organic polymers for electrical energy storage.

Flexible films having high dielectric constants with low dielectric loss have promising application in the emerging area of high‐energy‐density materials. Here, for the first time, an organometallic, Sn‐polyester‐containing hybrid free‐standing film in polyimide matrix is reported. Polyimide, pBTDA‐HDA, is used with poly(dimethyltin glutarate) and poly(dimethyltin‐3,3‐dimethyglutarate) (pDMTDMG) for having a processable film with tunable dielectric properties. Hybrid film with 60% pDMTDMG and 40% PI (HB2) is found to have improved dielectric features over previously synthesized organic polyimide and organometallic Sn‐polyester homopolymers. These novel organometallic–organic hybrid systems expanded a new area of dielectrics for next‐generation electronics with superior overall electrical performance.

Hybrid free standing films of tin-polyester with polyimide are prepared by blending process which exhibit tunable dielectric constants. The maximum achievable dielectric constant for hybrid systems have 60% load of tin-polyester and their dielectric values raging from ca. 5.5-6.2, close to that of the tin homopolymers. These values show improvement over polyimide p(BTDA-HDA) having a dielectric constant of ca. 3.5 with minimum frequency dispersion maintaining low dissipation factor. The hybrid systems of 60% p(DMTDMG) with 40% polyimide stand out by their morphological and electrical properties showing a breakdown strength of 464 MV/m, with a maximum energy density of 5.9 J/cm³, slightly higher than the commercial standard BOPP with improved operational temperature ca. 140 ^oC. Figure 1

Dielectric materials are a class of materials that are polarized under an electric field. Typically, highly polarizable, or high dielectric materials are used in energy storage applications such as a capacitor. Materials that have high dielectric constant, low dielectric loss, and high breakdown strength, have high energy density. Other important criteria for choosing a dielectric candidate include good thermal and mechanical stability. For their ease of processability and light weight applications, many polymer dielectrics are currently used commercially. Moreover, research to discover new materials to meet growing demand for lighter and more efficient materials has been ongoing.This article provides information on the basic principles of a capacitor, what makes a good dielectric material for capacitor energy storage applications, common dielectric polymers and their properties, as well as the exploration of next generation dielectric materials. Finally, an examination of current efforts to explore new dielectric materials and how they can be further tuned with the help of theoretical computations and experimental validation, are discussed.

Electrocardiography (ECG) is an essential technique for analyzing and monitoring cardiovascular physiological conditions such as arrhythmia. This article demonstrates the integration of screen printed ECG circuitry from a commercially available conducting polymer, PEDOT:PSS, onto commercially available finished textiles. ECG signals were recorded in dry skin conditions due to the ability of PEDOT:PSS to function as both ionic and electronic conductors. The signal amplifies when the skin transpires water vapor, or by applying a common lotion on the skin. Finally, PEDOT:PSS wires connected to PEDOT:PSS electrodes has been shown to record ECG signals comparable to Ag/AgCl connected to copper wires. Keywords: PEDOT:PSS, screen printing, electrocardiogram, mixed conduction, wearable electronics

Dielectric film capacitors with high energy density represent some of the most pervasive devices used in electrical and electronic systems. With the rapid growing demands in electrification, new polymer film dielectrics with high dielectric constant and high breakdown strength are needed. A toluene diisocyanate (TDI) based organic polymer with a flexible diaminoether backbone (EDR148™) was synthesized and fabricated into ~10 μm films by a blade cast method. Systematic dielectric spectroscopy study was performed to characterize the complex dielectric spectra over a broad range of frequencies and temperatures to probe global, segmental, and local relaxations. Furthermore, high field characterizations were conducted by using a D-E polarization loop tester and a specially designed pre-breakdown conduction measurement system for the fundamental understanding of the relationship between molecular structure and high filed polarization and breakdown. TDI-EDR148 exhibited a high dielectric constant of > 6 with a low loss factor of ~1.5% and a high breakdown strength of >600 MV/m. These properties represent a high energy density of ~12 J/cc for this aromatic polyuria film. The result was compared with a previously studied high K polymer to correlate and reveal mechanism leading to the design of polymers with high dipolar energy density.

A rational co-design process involves a synergistic approach towards the synthesis and development of new dielectric materials with high throughput screening and testing. This approach is gradually replacing the traditional Edisonian approach of using trial and error to a more sophisticated, data driven, approach for designing next generation dielectric materials. Recently, advancements in dielectric materials are achieved by the incorporation of group 14 metal in the main chain of polymer as an organometallic systems. Here in, we introduce transition metal based metal-organic framework (MOF) polymers as a dielectric materials. Transition metals zinc and cadmium are incorporated in the main chain of polymer through metal-oxygen bonds with varying number of methylene spacers in the repeat units. High molecular weight coordination complex polyesters are obtained, which exhibit high band gaps and low loss compared to their oxide counterparts while maintaining high dielectric constants. The rational co-design of these materials are motivated by DFT computations of the electronic, ionic and total dielectric constant contributions, band gap energies, along with their structural predictions of the local environments. Polymers are characterized with Nuclear Magnetic Resonance Spectroscopy (¹H-NMR), Fourier Transform Infrared Spectroscopy (FTIR) and with X-Ray Diffraction (XRD) for their structural properties and features which shows strong correlation to the experimental findings. Thermal behaviors are observed with Thermogravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC). Dielectric Spectroscopy and Optical Band Gap are measured and found strong correlation with the Density Functional Theory (DFT) predictions. These initial studies give insight into the potential advantages an expansion of chemical space for energy storage applications through a rational co-design approach. This work provides valuable validation and feedback to computational predictions to fulfill the goals of this approach.