Ultrathin, all-organic, fabric-based ferroelectret loudspeaker for wearable electronics.

All-organic, flexible, and body-compatible loudspeakers have become increasingly attractive for wearable electronics. Due to their remarkable piezoelectric response, ferroelectrets are suitable for loudspeakers. Two distinct kinds of ultrathin ferroelectrets, including cellular polypropylene films and expanded polytetrafluoroethylene (ePTFE) films, were combined with three different types of electrodes ((Poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS))-coated fabrics, PEDOT:PSS direct coating, and sputter-coated Au/Pd) for study regarding their frequency-dependent sound intensity and radiation directivity.

Poly(cannabinoid)s: Hemp-Derived Biocompatible Thermoplastic Polyesters with Inherent Antioxidant Properties.

The legalization of hemp cultivation in the United States has caused the price of hemp-derived cannabinoids to decrease 10-fold within 2 years. Cannabidiol (CBD), one of many naturally occurring diols found in hemp, can be purified in high yield for low cost, making it an interesting candidate for polymer feedstock. In this study, two polyesters were synthesized from the condensation of either CBD or cannabigerol (CBG) with adipoyl chloride.

Flexible cyclic-olefin with enhanced dipolar relaxation for harsh condition electrification.

Flexible large bandgap dielectric materials exhibiting ultra-fast charging-discharging rates are key components for electrification under extremely high electric fields. A polyoxafluoronorbornene (-POFNB) with fused five-membered rings separated by alkenes and flexible single bonds as the backbone, rather than conjugated aromatic structure typically for conventional high-temperature polymers, is designed to achieve simultaneously high thermal stability and large bandgap. In addition, an asymmetrically fluorinated aromatic pendant group extended from the fused bicyclic structure of the backbone imparts -POFNB with enhanced dipolar relaxation and thus high dielectric constant without sacrificing the bandgap.

All-Organic Flexible Ferroelectret Nanogenerator with Fabric-Based Electrodes for Self-Powered Body Area Networks.

Due to their electrically polarized air-filled internal pores, optimized ferroelectrets exhibit a remarkable piezoelectric response, making them suitable for energy harvesting. Expanded polytetrafluoroethylene (ePTFE) ferroelectret films are laminated with two fluorinated-ethylene-propylene (FEP) copolymer films and internally polarized by corona discharge. Poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS)-coated spandex fabric is employed for the electrodes to assemble an all-organic ferroelectret nanogenerator (FENG).

Flexible Temperature-Invariant Polymer Dielectrics with Large Bandgap.

Flexible dielectrics operable under simultaneous electric and thermal extremes are critical to advanced electronics for ultrahigh densities and/or harsh conditions. However, conventional high-performance polymer dielectrics generally have conjugated aromatic backbones, leading to limited bandgaps and hence high conduction loss and poor energy densities, especially at elevated temperatures. A polyoxafluoronorbornene is reported, which has a key design feature in that it is a polyolefin consisting of repeating units of fairly rigid fused bicyclic structures and alkenes separated by freely rotating single bonds, endowing it with a large bandgap of ≈5 eV and flexibility, while being temperature-invariantly stable over -160 to 160 °C.

Graphene and Poly(3,4-ethylene dioxythiophene):Poly(4-styrenesulfonate) on Nonwoven Fabric as a Room Temperature Metal and Its Application as Dry Electrodes for Electrocardiography.

Highly conductive, metal-like poly(ethylene terephthalate) (PET) nonwoven fabric was prepared by coating poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) containing dimethyl sulfoxide (DMSO) onto PET nonwoven fabric previously coated with graphene/graphite. The sheet resistance of the original nonwoven fabric decreases from >80 MΩ□ to 1.1 Ω□ after coating with 10.

Sn-Polyester/Polyimide Hybrid Flexible Free-Standing Film as a Tunable Dielectric Material.

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.

Screen-Printed PEDOT:PSS Electrodes on Commercial Finished Textiles for Electrocardiography.

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.

PEDOT:PSS "Wires" Printed on Textile for Wearable Electronics.

Herein, the fabrication of all-organic conductive wires is demonstrated by utilizing patterning techniques such as inkjet printing and sponge stencil to apply poly(3,4-ethylenedioxythiophene) polystyrenesulfonate (PEDOT:PSS) onto nonwoven polyethylene terephthalate (PET) fabric. The coating of the conducting polymer is only present on the surface of the substrate (penetration depth ∼ 200 μm) to retain the functionality and wearability of the textile. The wires fabricated by different patterning techniques provide a wide range of resistance, i.

Optimization of Organotin Polymers for Dielectric Applications.

Recently, there has been a growing interest in developing wide band gap dielectric materials as the next generation insulators for capacitors, photovoltaic devices, and transistors. Organotin polyesters have shown promise as high dielectric constant, low loss, and high band gap materials. Guided by first-principles calculations from density functional theory (DFT), in line with the emerging codesign concept, the polymer poly(dimethyltin 3,3-dimethylglutarate), p(DMTDMG), was identified as a promising candidate for dielectric applications.

Rational Co-Design of Polymer Dielectrics for Energy Storage.

Although traditional materials discovery has historically benefited from intuition-driven experimental approaches and serendipity, computational strategies have risen in prominence and proven to be a powerful complement to experiments in the modern materials research environment. It is illustrated here how one may harness a rational co-design approach-involving synergies between high-throughput computational screening and experimental synthesis and testing-with the example of polymer dielectrics design for electrostatic energy storage applications. Recent co-design efforts that can potentially enable going beyond present-day "standard" polymer dielectrics (such as biaxially oriented polypropylene) are highlighted.

Poly(dimethyltin glutarate) as a prospective material for high dielectric applications.

Poly(dimethyltin glutarate) is presented as the first organometallic polymer, a high dielectric constant, and low dielectric loss material. Theoretical results correspond well in terms of the dielectric constant. More importantly, the dielectric constant can be tuned depending on the solvent a film of the polymer is cast from.

Effect of incorporating aromatic and chiral groups on the dielectric properties of poly(dimethyltin esters).

High-dielectric constant materials are critical for numerous applications such as photovoltaics, photonics, transistors, and capacitors. There are numerous polymers used as dielectric layers in these applications but can suffer from having a low dielectric constant, small band gap, or ferroelectricity. Here, the structure-property relationship of various poly(dimethyltin esters) is described that look to enhance the dipolar and atomic polarization component of the dielectric constant.

Color-tuning neutrality for flexible electrochromics via a single-layer dual conjugated polymer approach.

A method to color-tune electrochromic devices through the use of theoretical calculations is demonstrated to achieve neutrality using only three monomers that form two distinct copolymers. These devices exhibit photopic contrasts up to ca. 38%, high neutrality, color uniformity, and switch speeds of less than 1 s.

Rational design of all organic polymer dielectrics.

To date, trial and error strategies guided by intuition have dominated the identification of materials suitable for a specific application. We are entering a data-rich, modelling-driven era where such Edisonian approaches are gradually being replaced by rational strategies, which couple predictions from advanced computational screening with targeted experimental synthesis and validation. Here, consistent with this emerging paradigm, we propose a strategy of hierarchical modelling with successive downselection stages to accelerate the identification of polymer dielectrics that have the potential to surpass 'standard' materials for a given application.

Neutral color tuning of polymer electrochromic devices using an organic dye.

Herein, we present a facile, one-step method to color tune electrochromic devices (ECDs) that switch between two neutral colors via in situ electrochemical polymerization of electroactive monomers in the presence of a small molecule organic yellow dye using all commercially available materials. These devices exhibited photopic contrasts of ca. 30% without background correction when assembled on flexible PET-ITO substrates.

Rationally designed polyimides for high-energy density capacitor applications.

Development of new dielectric materials is of great importance for a wide range of applications for modern electronics and electrical power systems. The state-of-the-art polymer dielectric is a biaxially oriented polypropylene (BOPP) film having a maximal energy density of 5 J/cm(3) and a high breakdown field of 700 MV/m, but with a limited dielectric constant (∼2.2) and a reduced breakdown strength above 85 °C.

Acrylated poly(3,4-propylenedioxythiophene) for enhancement of lifetime and optical properties for single-layer electrochromic devices.

We utilized our in situ method for the one-step assembly of single-layer electrochromic devices (ECDs) with a 3,4-propylenedioxythiophene (ProDOT) acrylate derivative, and long-term stability was achieved. By coupling the electroactive monomer to the cross-linkable polymer matrix, preparation of the electrochromic ProDOT polymer can occur followed by UV cross-linking. Thus, we achieve immobilization of the unreacted monomer, which prevents any degradative processes from occurring at the counter electrode.

Solid-state high-throughput screening for color tuning of electrochromic polymers.

Diffusion of two monomers and their oxidative copolymerization inside a solid-state gel electrolyte is utilized as a method to match the monomer feed ratio to a color resulting from a conjugated copolymer having a single absorption in the visible region. Here, a combination of two monomers is used to generate a solid-state electrochromic device of any color, except black and green, in the colored state with all other colors going to transmissive sky blue in the bleached state.

Color tuning of black for electrochromic polymers using precursor blends.

We demonstrate a facile controlling of the optical and colorimetric properties of a donor-acceptor conjugated polymer simply by varying the mix ratio of two precursors in a precursor blend. The conversion of a precursor blend results in an entirely new donor-acceptor polymer, distinct from the conjugated polymer of each precursor. Careful optimization of the mix ratio of two precursors results in a black electrochromic polymer.

Three dye energy transfer cascade within DNA thin films.

An efficient cascade FRET was realized in solid state DNA-CTMA thin films using a three chromophore system without any covalent attachments. The extent of energy transfer from Cm102 to SRh was studied and found to improve eight-fold using the bridging dye Pm567.

Polymer-mediated cyclodehydration of alditols and ketohexoses.

The polymer PEDOT(+) (1 or 2) mediates a cyclodehydration reaction with alditols 3, 5, 7, 9, in hydrocarbon solvents, to give cyclic ethers 4, 6, 8, or 10, respectively, in high yield with a trivial isolation protocol. Polymers 1 or 2 also mediate the cyclodehydration of ketohexoses such as d-fructose, but not aldohexoses, to the important industrial intermediate 5-hydroxymethylfurfural (17), under milder conditions when compared to reactions mediated by mineral acids. A cascade reaction with ketohexoses is observed in toluene via cyclodehydration followed by Friedel-Crafts alkylation of the initially formed benzylic alcohol to give 16.

Inkjet-printed gold nanoparticle electrochemical arrays on plastic. Application to immunodetection of a cancer biomarker protein.

Electrochemical detection combined with nanostructured sensor surfaces offers potentially low-cost, high-throughput solutions for detection of clinically significant proteins. Inkjet printing offers an inexpensive non-contact fabrication method for microelectronics that is easily adapted for incorporating into protein immunosensor devices. Herein we report the first direct fabrication of inkjet-printed gold nanoparticle arrays, and apply them to electrochemical detection of the cancer biomarker interleukin-6 (IL-6) in serum.