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A family of dioxythiophene (DOT)-based conjugated random copolymers, capable of reversibly switching between a neutral black and an oxidized transmissive state, are reported for electrochromic (EC) applications. By replacing 3,4-ethylenedioxythiophene (EDOT) in the previous generation of a core donor–acceptor–donor (D–A–D) terheterocycle with a methyl-alkylated 3,4-propylenedioxythiophene (ProDOT), we enhance the solubility of precursors and monomers in this new generation of broadly absorbing electrochromic polymers (ECPs). By adjusting the newly designed terheterocycle monomer feed ratio, we obtain three polymers with varying hues of color neutrality (a* and b* < ±10) throughout the entire switching voltage range and with integrated contrasts 45–49% throughout the visible region (380–700 nm). The a* values of the polymers ranged between −8 (green hue) and +5 (red hue), with their b* values ranging between −4 and −7 (blue hue) in their neutral states; additionally, the a* and b* values are all below ±8 i...

The unique ability of combined ionic and electronic transport in conjugated, semiconducting polymers has resulted in the emergence of a variety of redox-based technologies ranging from energy stora...

Electrochromic (EC) materials and devices provide a user-controlled, dynamic way of displaying information using low power, making them interesting for a range of applications in numerous markets, including logistics, retail, consumer goods, and health care. To optimize the cost while simplifying the production, expanding the color space, and enhancing the contrast and vibrancy of EC displays aimed for cost-sensitive products, we sought to reduce the number of layers as well as remove the underlying conducting layer that accounts for a substantial fraction of the cost of a printed label. Here, we show how conjugated electrochromic polymers, which are inherently semiconducting, can be used to accomplish this goal and afford printable EC displays with a flexible form factor. Using a combination of electrochemical probes, in situ spectroscopy, solid-state conductivity, and in situ conductance measurements, we have studied and compared five different EC polymers with conductivities spanning multiple orders of magnitude and colors that span most of the visible range, identifying polymers and properties that allow for switching from the colored to the clear state without an underlying conducting layer. Finally, we incorporate these EC polymers into optimized flexible devices without an underlying conductor and demonstrate that they are able to provide on-demand, reversible colored-to-clear switching on the order of seconds to minutes, with operating voltages below ±1 V, optical memories exceeding 60 min, and a shelf-life exceeding 12 months.

To achieve optimal performance in a conjugated polymer-based electrochemical device, i.e. for a supercapacitor to reach full depth of discharge or for an electrochromic device (ECD) to achieve maximum contrast, the two electrodes must be in different oxidation states when the device is assembled. Here, we evaluate the use of chemical oxidation as a scalable postprocessing method to adjust the redox state of polymer-coated electrodes. We evaluate how the extent of oxidation depends on both the redox properties of the conjugated polymer and on the choice of chemical oxidant, and how these parameters affect the functionality of the film. Comparing Ag(I) and Fe(III) oxidants, we find that it is not the oxidizing power that determines the extent of doping but rather the redox potentials of the polymers, with the more easily oxidized polymers doping to a higher extent. Because the polarity and surface energy of the polymer changes upon oxidation, we also show how a phosphonic acid surface pre-treatment improves interfacial adhesion between the polymer and a transparent oxide electrode (ITO). Finally, as a proof of principle, we demonstrate how chemical oxidation of the organic counter electrode a minimally color changing dioxypyrrole polymer enhances the device contrast of an ECD, confirming that this approach is a promising route toward high-throughput manufacturing of ECDs and other polymer-based electrochemical devices.

This chapter aims to teach general concepts and structure–property relationships that govern color and provides electrochromic switching control. It focuses on soluble and high molecular weight electrochromic polymers. The chapter draws on systems that can switch between a colored and a clear state as these require color tuning both in the neutral and charged state. It demonstrates how to expand the range of accessible colors, as well as how switching to a more colorless oxidized state can be achieved. Electrochromism refers to the ability of a material to reversibly change its electromagnetic spectrum when undergoing a redox process. While the determination of optical contrast is a relatively straightforward measurement that can be done using a simple spectrophotometer, quantitative comparisons between materials in the literature is not trivial. The switching time is highly dependent on experimental parameters such as electrolyte concentration, cell geometry, film thickness, and substrate resistance.

Pulmonary arterial hypertension (PAH) is a chronic and progressive disorder characterized by vascular remodeling of the small pulmonary arteries, resulting in elevated pulmonary vascular resistance and ultimately, right ventricular failure. Expanded understanding of PAH pathophysiology as it pertains to the nitric oxide (NO), prostacyclin (prostaglandin I2) (PGI2) and endothelin-1 pathways has led to recent advancements in targeted drug development and substantial improvements in morbidity and mortality. There are currently several classes of drugs available to target these pathways including phosphodiesterase-5 inhibitors (PDE5i), soluble guanylate cyclase (sGC) stimulators, prostacyclin class agents and endothelin receptor antagonists (ERAs). Combination therapy in PAH, either upfront or sequentially, has become a widely adopted treatment strategy, allowing for simultaneous targeting of more than one of these signaling pathways implicated in disease progression. Much of the current treatment landscape has focused on initial combination therapy with ambrisentan and tadalafil, an ERA and PDE5I respectively, following results of the AMBITION study demonstrating combination to be superior to either agent alone as upfront therapy. Consequently, clinicians often consider combination therapy with other drugs and drug classes, as deemed clinically appropriate, for patients with PAH. An alternative regimen that targets the NO and PGI2 pathways has been adopted by some clinicians as an effective and sometimes preferred therapeutic combination for PAH. Although there is a paucity of prospective data, preclinical data and results from secondary data analysis of clinical studies targeting these pathways may provide novel insights into this alternative combination as a reasonable, and sometimes preferred, alternative approach to combination therapy in PAH. This review of preclinical and clinical data will discuss the current understanding of combination therapy that simultaneously targets the NO and PGI2 signaling pathways, highlighting the clinical advantages and theoretical biochemical interplay of these agents.

The use of superhydrophilic surfaces for superwetting applications can be hampered by their wetting degradation over time. In this work, superhydrophilic surfaces were fabricated by graphene oxide (GO) deposition on roughened polyvinyl chloride (PVC) substrates. These surfaces were found to exhibit zero contact angle when enhanced green fluorescent protein (EGFP) was deposited on the surface immediately after GO was applied. However, when the GO-coated substrate was stored for 3 h, the surface displayed a contact angle of 54°. The main contact line spreading of the EGFP drop was more easily discernible using normal (500 lx, low glare and shadow free) lighting than with blue LED lighting in the dark. The average radius of the spreading main contact line was found to follow a power-law relationship that increased at a faster rate with higher relative humidity. Confocal imaging revealed rings of EGFP deposition following superwetting that is attributable to pinning around the islands of GO accumulation. Substrate superhydrophilic and superwetting properties can be preserved by adequate control of relative humidity. Relative humidity of 80 % was easily maintained for 150 min by incorporating a 20 μL water drop in a sealed 240-mL container.

A drop-based approach to facilitate the remediation of methylene blue (MB) solution via catalytic degradation with silver nanowires on a superhydrophobic substrate with a 2 mm hole without fouling is presented here. Studies on the dynamical response of drop removal via pressure rate perturbation, showed greater elapsed times at the 7.61 μL/s air flowrate with 25 μL and 30 μL volume drops than at higher air flowrates used. These results are accounted for by the rate of air flow through the plastron, used to equilibrate the lowering of pressure in the transparent receptacle that tends to prevent drop dislodgement, being only able to operate up to a specific upper limit. A method that calculates the absorbance values based on the intensity spectrum of the nanowire solution as reference was found to reveal the time progress degradation of MB solution by spectrometry. It showed that a 25 μL drop of the MB solution could be degraded within 15 s using 0.25 mg of the silver nanowire.

The design of high bandgap electrochromic polymers (ECPs) that switch from a high energy absorbing colored state to a near-IR absorbing colorless state requires a challenging balance to be struck between achieving large changes in the absorption profile while maintaining sufficiently low oxidation potentials for use in full-color electrochromic devices. Previous studies on high bandgap ECPs have investigated structure–property relationships in dioxythiophenes copolymerized with various arylenes. Here, we expand this understanding by looking more closely at the effect of the dioxythiophene moiety as well as by varying the substituents on the arylene moiety. Three ECPs have been synthesized to perform this study with repeat units composed of electron-rich dimethoxyphenylene in alternation with dimers of 3,4-dialkoxy- and 3,4-propylenedioxythiophenes, yielding high gap polymers that are vibrant yellow or orange in the charge neutral state. Comparing these newly synthesized polymers to a structurally similar ...

Dry ice (solid CO2) remains highly useful when temperature-sensitive biological samples need to be cryogenically transported. CO2 released during the sublimation of dry ice can diffuse through gas permeable receptacle material or any defective seals resulting in potential sample acidification and compromised integrity. In addition, the quality of cryopreservation can be undermined once the dry ice is exhausted. The dry ice carrier design described here has been demonstrated to prevent sublimated CO2 from reaching the samples while maintaining storage temperature below −60 °C for 19 h. It is also equipped with microcontroller-based temperature monitoring for traceability and CO2 gas monitoring for safety.

Liquid marbles to separate wetting (silver nanowires) from non-wetting (graphite and talcum) particles is described here. Two types of liquid marbles are formed by coating the dry mixture test material on pendant or sessile drops. The silver nanowire particles are separated from the graphite or talcum shell by entering into the liquid core of the marbles. The liquid core is extracted into capillary tubes where the presence of silver nanoparticles was confirmed by a blue to colourless change arising from silver-mediated catalytic reduction of methylene blue and sodium borohydride solution. The use of an inclined rotating surface to coat the pendant drop was found to create liquid marbles in a more controllable manner. A platform tilt angle of 15o followed by rotation was found to provide more uniform albeit only partially coating the bottom of the pendant drop.

This work reports on the performance of a segmented polymer electrochromic display that was fabricated with solution-based processes in ambient atmosphere. An encapsulation process and the combination of structured wells for the polymer electrochrome and electrolyte layers as well as the use of a preoxidized counter polymer yields high contrasts and fast switching speeds. Asymmetric driving-with respect to time-of the display is investigated for the first time and the degradation effects in the electrochrome layer are analyzed and addressed to yield a stable device exceeding 100,000 switching cycles. A printed circuit board was integrated with the display, allowing the device to be run as a clock, where the segments only required short pulses to switch without the need for a constant current to maintain its state. Such an application pairs well with the advantages of electrochromic polymers, drawing on its high contrast, stability, and ability to maintain its colored or colorless state without the need for a constant power supply, to demonstrate the promise as well as the challenges of developing more sophisticated electrochromic devices.

Throughout the literature, a variety of counter electrode materials have been used in conjugated polymer-based electrochromic devices (ECDs) without a comparative understanding of their effects on the electrochromic properties of the device. In this study, we show that poor ECD performance, often attributed to electrochromic polymer (ECP) stability, is in fact largely due to an inappropriate choice of counter electrode. We have compared a set of counter electrode materials used in the ECD literature in magenta-to-clear and black-to-clear devices and evaluated how they affect the device parameters including contrast, switching time, stability, and voltage requirements. We demonstrate that through the appropriate choice of counter electrode material (i) the operating voltage can be lowered, (ii) no additional equilibration/break-in time is required, and (iii) the contrast and switching times of the ECP is maintained when incorporated into a device. Furthermore, we show that even unencapsulated ECDs with ECP-Magenta as the vibrantly colored material assembled and operated under ambient conditions can withstand over 10 000 switches without compromising contrast or switching time.

Propylenedioxythiophene (ProDOT) polymers are synthesized using an oxidative polymerization route that results in methacrylate substituted poly(ProDOTs) having a Mn of 10–20 kDa wherein the methacrylate functionality constitutes from 6 to 60% of the total monomer units. Solutions of these polymers show excellent film forming abilities, with thin films prepared using both spray-casting and spin-coating. These polymers are demonstrated to crosslink upon UV irradiation at 350 nm, in the presence of an appropriate photoinitiator, to render the films insoluble to common organic solvents. Electrochemical, spectroelectrochemical, and colorimetric analyses of the crosslinked polymer films are performed to establish that they retain the same electrochromic qualities as the parent polymers with no detriment to the observed properties. To demonstrate applicability for multi-film processing and patterning, photolithographic patterning is shown, as is desired for fully solution processed and patterned devices.

Two terthiophenes incorporating the synthon 3,4-(1,2-phenylenedioxy)thiophene (PheDOT) have been developed. Specifically, 2,5-bisthienyl-3,4-(1,2-phenylenedioxy)thiophene (BTh-PheDOT 1) and 2,5-bisethylenedioxythienyl-3,4-(1,2-phenylenedioxy)thiophene (BEDOT-PheDOT 2) were electropolymerized to form electroactive polymer films (P1 and P2) that switched between two highly colored states with the more electron-rich EDOT derivative P2 observed to switch at a lower potential. Additionally, both P1 and P2 displayed moderate to low optical bandgaps of 1.8 and 1.6 eV, respectively. Crystal structures of BTh-PheDOT showed the monomer to be nearly planar with π -stacking observable between monomers. These findings demonstrate the potential of PheDOT as an electroactive synthon for the formation of well-ordered systems.

We report on the optimization of the capacitive behavior of poly(3,4-ethylenedioxythiophene) (PEDOT) films as polymeric electrodes in flexible, Type I electrochemical supercapacitors (ESCs) utilizing ionic liquid (IL) and organic gel electrolytes. The device performance was assessed based on figures of merit that are critical to evaluating the practical utility of electroactive polymer ESCs. PEDOT/IL devices were found to be highly stable over hundreds of thousands of cycles and could be reversibly charged/discharged at scan rates between 500 mV/s and 2 V/s depending on the polymer loading. Furthermore, these devices exhibit leakage currents and self-discharge rates that are comparable to state of the art electrochemical double-layer ESCs. Using an IL as device electrolyte allowed an extension of the voltage window of Type I ESCs by 60%, resulting in a 2.5-fold increase in the energy density obtained. The efficacies of tjese PEDOT ESCs were assessed by using them as a power source for a high-contrast and fast-switching electrochromic device, demonstrating their applicability in small organic electronic-based devices.