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1.
Nano Lett ; 2024 Jul 12.
Artículo en Inglés | MEDLINE | ID: mdl-38994869

RESUMEN

Metasurfaces have revolutionized optical technologies by offering powerful, compact, and versatile solutions to control light. Conducting polymers, characterized by their conjugated molecular structures, facilitate charge transport and exhibit interesting electrical, optical, and mechanical properties. Integrating conducting polymers with optical metasurfaces can unlock new opportunities and functionalities in modern optics. In this work, we demonstrate an electrochemically programmable metasurface with independently controlled metasurface pixels at optical frequencies. Electrochemical modulation of locally conjugated polyaniline on gold nanorods, which are arranged on addressable electrodes according to the Pancharatnam-Berry phase design, enables dynamic control over the metasurface pixels into programmable configurations. With the same metasurface device, we showcase diverse optical functions, including dynamic beam diffraction and varifocal lensing along and off the optical axis. The synergy between flat optics and conducting polymer science holds immense potential to enhance the performance and function versatility of metasurfaces, paving the way for innovative optical applications.

2.
Small ; 20(12): e2307565, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-37946670

RESUMEN

Liquid crystal elastomers (LCEs) with promising applications in the field of actuators and soft robotics are reported. However, most of them are activated by external heating or light illumination. The examples of electroactive LCEs are still limited; moreover, they are monofunctional with one type of deformation (bending or contraction). Here, the study reports on trilayer electroactive LCE (eLCE) by intimate combination of LCE and ionic electroactive polymer device (i-EAD). This eLCE is bi-functional and can perform either bending or contractile deformations by the control of the low-voltage stimulation. By applying a voltage of ±2 V at 0.1 Hz, the redox behavior and associated ionic motion provide a bending strain difference of 0.80%. Besides, by applying a voltage of ±6 V at 10 Hz, the ionic current-induced Joule heating triggers the muscle-like linear contraction with 20% strain for eLCE without load. With load, eLCE can lift a weight of 270 times of eLCE-actuator weight, while keeping 20% strain and affording 5.38 kJ·m-3 work capacity. This approach of combining two smart polymer technologies (LCE and i-EAD) in a single device is promising for the development of smart materials with multiple degrees of freedom in soft robotics, electronic devices, and sensors.

3.
Nanotechnology ; 35(35)2024 Jun 11.
Artículo en Inglés | MEDLINE | ID: mdl-38154133

RESUMEN

NonlinearI-Vcharacteristics associated with Coulomb blockade (CB) in conducting polymers were systematically investigated. At low temperatures, a crossover from Ohmic to nonlinear behavior was observed, along with drastically enhanced noise in differential conductance right from the crossover. The fluctuation can be well explained by the Coulombic oscillation in the collective percolation system, where the charge transport is related to the Coulombic charging energy between crystalline domains. Furthermore, a distinct quantum conductance, the fingerprint of CB caused by the individual tunneling between crystalline grains, was observed in sub-100 nm devices, confirming a strong association between nonlinearI-Vcharacteristics and CB effect.

4.
Macromol Rapid Commun ; 45(1): e2300237, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-37232260

RESUMEN

Conducting polymers like polyaniline (PANI) are promising pseudocapacitive electrode materials, yet experience instability in cycling performance. Since polymers often degrade into oligomers, short chain length anilines have been developed to improve the cycling stability of PANI-based supercapacitors. However, the capacitance degradation mechanisms of aniline oligomer-based materials have not been systematically investigated and are little understood. Herein, two composite electrodes based on aniline trimers (AT) and carbon nanotubes (CNTs) are studied as model systems and evaluated at both pre-cycling and post-cycling states through physicochemical and electrochemical characterizations. The favorable effect of covalent bonding between AT and CNTs is confirmed to enhance cycling stability by preventing the detachment of aniline trimer and preserving the electrode microstructure throughout the charge/discharge cycling process. In addition, higher porosity has a positive effect on electron/ion transfer and the adaptation to volumetric changes, resulting in higher conductivity and extended cycle life. This work provides insights into the mechanism of enhanced cycling stability of aniline oligomers, indicating design features for aniline oligomer electrode materials to improve their electrochemical performance.


Asunto(s)
Nanotubos de Carbono , Polímeros , Polímeros/química , Nanotubos de Carbono/química , Compuestos de Anilina/química
5.
Macromol Rapid Commun ; 45(14): e2400074, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38593474

RESUMEN

Redox-conducting polymers based on SalEn-type complexes have attracted considerable attention due to their potential applications in electrochemical devices. However, their charge transfer mechanisms, physical and electrochemical properties remain unclear, hindering their rational design and optimization. This study aims to establish the influence of monomer geometry on the polymer's properties by investigating the properties of novel nonplanar SalEn-type complexes, poly[N,N'-bis(salicylidene)propylene-2-(hydroxy)diaminonickel(II)], and its analog with 2,2,6,6-tetramethylpiperidinyl-N-oxyl (TEMPO)-substituted bridge (MTS). To elucidate the charge transfer mechanism, operando UV-Vis spectroelectrochemical analysis, electrochemical impedance spectroscopy, and electron paramagnetic resonance are employed. Introducing TEMPO into the bridge moiety enhanced the specific capacity of the poly(MTS) material to 95 mA h g-1, attributed to TEMPO's and conductive backbone's charge storage capabilities. Replacement of the ethylenediimino-bridge with a 1,3-propylenediimino- bridge induced significant changes in the complex geometry and material's morphology, electrochemical, and spectral properties. At nearly the same potential, polaron and bipolaron particles emerged, suggesting intriguing features at the overlap point of the electroactivity potentials ranges of polaron-bipolaron and TEMPO, such as a disruption in the connection between TEMPO and the conjugation chain or intramolecular charge transfer. These results offer valuable insights for optimizing strategies to create organic materials with tailored properties for use in catalysis and battery applications.


Asunto(s)
Óxidos N-Cíclicos , Oxidación-Reducción , Polímeros , Óxidos N-Cíclicos/química , Polímeros/química , Polímeros/síntesis química , Etilenodiaminas/química , Estructura Molecular , Técnicas Electroquímicas , Conductividad Eléctrica
6.
Macromol Rapid Commun ; 45(1): e2300229, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-37357826

RESUMEN

Functional inks for light-based 3D printing are actively being searched for being able to exploit all the potentialities of additive manufacturing. Herein, a fast visible-light photopolymerization process is showed of conductive PEDOT:PSS hydrogels. For this purpose, a new Type II photoinitiator system (PIS) based on riboflavin (Rf), triethanolamine (TEA), and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) is investigated for the visible light photopolymerization of acrylic monomers. PEDOT:PSS has a dual role by accelerating the photoinitiation process and providing conductivity to the obtained hydrogels. Using this PIS, full monomer conversion is achieved in less than 2 min using visible light. First, the PIS mechanism is studied, proposing that electron transfer between the triplet excited state of the dye (3 Rf*) and the amine (TEA) is catalyzed by PEDOT:PSS. Second, a series of poly(2-hydroxyethyl acrylate)/PEDOT:PSS hydrogels with different compositions are obtained by photopolymerization. The presence of PEDOT:PSS negatively influences the swelling properties of hydrogels, but significantly increases its mechanical modulus and electrical properties. The new PIS is also tested for 3D printing in a commercially available Digital Light Processing (DLP) 3D printer (405 nm wavelength), obtaining high resolution and 500 µm hole size conductive scaffolds.


Asunto(s)
Aminas , Hidrogeles , Luz , Impresión Tridimensional
7.
Int J Mol Sci ; 25(3)2024 Jan 26.
Artículo en Inglés | MEDLINE | ID: mdl-38338846

RESUMEN

Conducting polymers (CPs) are an innovative class of materials recognized for their high flexibility and biocompatibility, making them an ideal choice for health monitoring applications that require flexibility. They are active in their design. Advances in fabrication technology allow the incorporation of CPs at various levels, by combining diverse CPs monomers with metal particles, 2D materials, carbon nanomaterials, and copolymers through the process of polymerization and mixing. This method produces materials with unique physicochemical properties and is highly customizable. In particular, the development of CPs with expanded surface area and high conductivity has significantly improved the performance of the sensors, providing high sensitivity and flexibility and expanding the range of available options. However, due to the morphological diversity of new materials and thus the variety of characteristics that can be synthesized by combining CPs and other types of functionalities, choosing the right combination for a sensor application is difficult but becomes important. This review focuses on classifying the role of CP and highlights recent advances in sensor design, especially in the field of healthcare monitoring. It also synthesizes the sensing mechanisms and evaluates the performance of CPs on electrochemical surfaces and in the sensor design. Furthermore, the applications that can be revolutionized by CPs will be discussed in detail.


Asunto(s)
Técnicas Biosensibles , Nanoestructuras , Polímeros/química , Técnicas Biosensibles/métodos , Tecnología , Carbono
8.
Int J Mol Sci ; 25(10)2024 May 20.
Artículo en Inglés | MEDLINE | ID: mdl-38791590

RESUMEN

This paper describes the process of producing chemiresistors based on hybrid nanostructures obtained from graphene and conducting polymers. The technology of graphene presumed the following: dispersion and support stabilization based on the chemical vapor deposition technique; transfer of the graphene to the substrate by spin-coating of polymethyl methacrylate; and thermal treatment and electrochemical delamination. For the process at T = 950 °C, a better settlement of the grains was noticed, with the formation of layers predominantly characterized by peaks and not by depressions. The technology for obtaining hybrid nanostructures from graphene and conducting polymers was drop-casting, with solutions of Poly(3-hexylthiophene (P3HT) and Poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-bithiophene] (F8T2). In the case of F8T2, compared to P3HT, a 10 times larger dimension of grain size and about 7 times larger distances between the peak clusters were noticed. To generate chemiresistors from graphene-polymer structures, an ink-jet printer was used, and the metallization was made with commercial copper ink for printed electronics, leading to a structure of a resistor with an active surface of about 1 cm2. Experimental calibration curves were plotted for both sensing structures, for a domain of CH4 of up to 1000 ppm concentration in air. A linearity of the curve for the low concentration of CH4 was noticed for the graphene structure with F8T2, presenting a sensitivity of about 6 times higher compared with the graphene structure with P3HT, which makes the sensing structure of graphene with F8T2 more feasible and reliable for the medical application of irritable bowel syndrome evaluation.


Asunto(s)
Grafito , Síndrome del Colon Irritable , Metano , Nanoestructuras , Polímeros , Grafito/química , Nanoestructuras/química , Polímeros/química , Metano/química , Síndrome del Colon Irritable/metabolismo , Humanos , Pruebas Respiratorias/métodos , Tiofenos/química , Conductividad Eléctrica
9.
Molecules ; 29(7)2024 Mar 29.
Artículo en Inglés | MEDLINE | ID: mdl-38611809

RESUMEN

Nowadays, drug delivery systems (DDSs) are gaining more and more attention. Conducting polymers (CPs) are efficiently used for DDS construction as such systems can be used in therapy. In this research, a well-known CP, polypyrrole (PPy), was synthesized in the presence of the polysaccharide heparin (HEP) and chlorpromazine (CPZ) using sodium dodecyl sulfate (SDS) as electrolyte on a steel substrate. The obtained results demonstrate the successful incorporation of CPZ and HEP into the polymer matrix, with the deposited films maintaining stable electrochemical parameters across multiple doping/dedoping cycles. Surface roughness, estimated via AFM analysis, revealed a correlation with layer thickness-decreasing for thinner layers and increasing for thicker ones. Moreover, SEM images revealed a change in the morphology of PPy films when PPy is electropolymerized in the presence of CPZ and HEP, while FTIR confirmed the presence of CPZ and HEP within PPy. Due to its lower molecular mass compared to HEP, CPZ was readily integrated into the thin polymer matrix during deposition, with diffusion being unimpeded, as opposed to films with greater thickness. Finally, the resulting system exhibited the ability to release CPZ, enabling a dosing range of 10 mg to 20 mg per day, effectively covering the therapeutic concentration range.


Asunto(s)
Clorpromazina , Polímeros , Pirroles , Sistemas de Liberación de Medicamentos , Heparina
10.
Molecules ; 29(6)2024 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-38542950

RESUMEN

Owing to their special structure and excellent physical and chemical properties, conducting polymers have attracted increasing attention in materials science. In recent years, tremendous efforts have been devoted to improving the comprehensive performance of conducting polymers by using the technique of "doping." Spherical polyelectrolyte brushes (SPBs) bearing polyelectrolyte chains grafted densely to the surface of core particles have the potential to be novel dopant of conducting polymers not only because of their spherical structure, high grafting density and high charge density, but also due to the possibility of their being applied in printed electronics. This review first presents a summary of the general dopants of conducting polymers. Meanwhile, conducting polymers doped with spherical polyelectrolyte brushes (SPBs) is highlighted, including the preparation, characterization, performance and doping mechanism. It is demonstrated that comprehensive performance of conducting polymers has improved with the addition of SPBs, which act as template and dopant in the synthesis of composites. Furthermore, the applications and future developments of conductive composites are also briefly reviewed and proposed, which would draw more attention to this field.

11.
Small ; 19(35): e2207100, 2023 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-37098606

RESUMEN

Materials are more easily damaged during accidents that involve rapid deformation. Here, a design strategy is described for electronic materials comprised of conducting polymers that defies this orthodox property, making their extensibility and toughness dynamically adaptive to deformation rates. This counterintuitive property is achieved through a morphology of interconnected nanoscopic core-shell micelles, where the chemical interactions are stronger within the shells than the cores. As a result, the interlinked shells retain material integrity under strain, while the rate of dissociation of the cores controls the extent of micelle elongation, which is a process that adapts to deformation rates. A prototype based on polyaniline shows a 7.5-fold increase in ultimate elongation and a 163-fold increase in toughness when deformed at increasing rates from 2.5 to 10 000% min-1 . This concept can be generalized to other conducting polymers and highly conductive composites to create "self-protective" soft electronic materials with enhanced durability under dynamic movement or deformation.

12.
Small ; 19(26): e2300689, 2023 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-36950756

RESUMEN

Solution-processable conducting polymers (CPs) are a compelling alternative to inorganic counterparts because of their potential for tuning chemical properties and creating flexible organic electronics. CPs, which typically comprise either only an electron donor (D) or its alternative combinations with an electron acceptor (A), exhibit charge transfer behavior between the units, resulting in an electrical conductivity suitable for utilization in electronic devices and for energy storage applications. However, the energy storage behavior of CPs with a sequence of electron acceptors (A-A), has rarely been investigated, despite their promising lower band gap and higher charge carrier mobility. Utilizing the aforesaid concept herein, four CPs featuring benzodithiophenedione (BDD), and diketopyrrolepyrrole (DPP) are synthesized. Among them, the BDDTH-DPPEH polymer exhibited the highest specific capacitance of 126.5 F g-1 at a current density of 0.5 A g-1 in an organic electrolyte over a wide potential window of -0.6-1.4 V. Notably, the supercapacitor properties of the polymeric electrode materials improved with increasing conjugation length by adding thiophene donor units and shortening the alkyl chain lengths. Furthermore, a symmetric supercapacitor device fabricated using BDDTH-DPPEH exhibited a high-power density of 4000 W kg-1 and an energy density of 31.66 Wh kg-1 .

13.
Small ; 19(35): e2301493, 2023 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-37093544

RESUMEN

Porous materials with multiple hierarchy levels can be useful as lightweight engineering structures, biomedical implants, flexible functional devices, and thermal insulators. Numerous routes have integrated bottom-up and top-down approaches for the generation of engineering materials with lightweight nature, complex structures, and excellent mechanical properties. It nonetheless remains challenging to generate ultralight porous materials with hierarchical architectures and multi-functionality. Here, the combined strategy based on Pickering emulsions and additive manufacturing leads to the development of ultralight conducting polymer foams with hierarchical pores and multifunctional performance. Direct writing of the emulsified inks consisting of the nano-oxidant-hydrated vanadium pentoxide nanowires-generated free-standing scaffolds, which are stabilized by the interfacial organization of the nanowires into network structures. The following in situ oxidative polymerization transforms the nano-oxidant scaffolds into foams consisting of a typical conducting polymer-polyaniline. The lightweight polyaniline foams featured by hierarchical pores and high surface areas show excellent performances in the applications of supercapacitor electrodes, planar micro-supercapacitors, and gas sensors. This emerging technology demonstrates the great potential of a combination of additive manufacturing with complex fluids for the generation of functional solids with lightweight nature and adjustable structure-function relationships.

14.
Small ; 19(15): e2205324, 2023 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-36634985

RESUMEN

With commercial electronics transitioning toward flexible devices, there is a growing demand for high-performance polymers such as poly(3,4-ethylenedioxythiophene): poly(styrene sulfonate) (PEDOT:PSS). Previous breakthroughs in promoting the conductivity of PEDOT:PSS, which mainly stem from solvent-treatment and transfer-printing strategies, remain as inevitable challenges due to the inefficient, unstable, and biologically incompatible process. Herein, a scalable fabrication of conducting PEDOT:PSS inks is reported via a metastable liquid-liquid contact (MLLC) method, realizing phase separation and removal of excess PSS simultaneously. MLLC-doped inks are further used to prepare ring-like films through a compromise between the coffee-ring effect and the Marangoni vortex during evaporation of droplets. The specific control over deposition conditions allows for tunable ring-like morphologies and preferentially interconnected networks of PEDOT:PSS nanofibrils, resulting in a high electrical conductivity of 6,616 S cm-1 and excellent optical transparency of the film. The combination of excellent electrical properties and the special morphology enables it to serve as electrodes for touch sensors with gradient pressure sensitivity. These findings not only provide new insight into developing a simple and efficient doping method for commercial PEDOT:PSS ink, but also offer a promising self-assembled deposition pattern of organic semiconductor films, expanding the applications in flexible electronics, bioelectronics as well as photovoltaic devices.

15.
Small ; 19(41): e2302388, 2023 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-37312396

RESUMEN

A promising anode material for Li-ion batteries, silicon (Si) suffers from volume expansion-induced pulverization and solid electrolyte interface (SEI) instability. Microscale Si with high tap density and high initial Coulombic efficiency (ICE) has become a more anticipated choice, but it will exacerbate the above issues. In this work, the polymer polyhedral oligomeric silsesquioxane-lithium bis (allylmalonato) borate (PSLB) is constructed by in situ chelation on microscale Si surfaces via click chemistry. This polymerized nanolayer has an "organic/inorganic hybrid flexible cross-linking" structure that can accommodate the volume change of Si. Under the stable framework formed by PSLB, a large number of oxide anions on the chain segment preferentially adsorb LiPF6 and further induce the integration of inorganic-rich, dense SEI, which improves the mechanical stability of SEI and provides accelerated kinetics for Li+ transfer. Therefore, the Si4@PSLB anode exhibits significantly enhanced long-cycle performance. After 300 cycles at 1 A g-1 , it can still provide a specific capacity of 1083 mAh g-1 . Cathode-coupled with LiNi0.9 Co0.05 Mn0.05 O2 (NCM90) in the full cell retains 80.8% of its capacity after 150 cycles at 0.5 C.

16.
Nanotechnology ; 34(20)2023 Mar 06.
Artículo en Inglés | MEDLINE | ID: mdl-36787629

RESUMEN

Blended films comprising poly(butyl acrylate) (PBA)-grafted cellulose nanocrystals (CNCs) and poly(3-hexylthiophene) (P3HT), exhibited more intense photoluminescence (PL) and longer PL emission lifetimes compared to pristine P3HT films. Optical absorption and photoluminescence spectra indicated reduced torsional disorder i.e. enhanced backbone planarity in the P3HT@CNC blended composites compared to the bare P3HT. Such molecule-level geometrical modification resulted in both smaller interchain and higher intrachain exciton bandwidth in the blended composites compared to the bare P3HT, because of reduced interchain interactions and enhanced intrachain order. These results indicate a potential switch of the aggregation behavior from dominant H-aggregates to J-aggregates, supported by Raman spectroscopy. The reorganization of micromolecular structure and concomitant macroscopic aggregation of the conjugated polymer chains resulted in a longer conjugation length for the P3HT@CNC blended composites compared to the bare P3HT. Additionally, this nanoscale morphological change produced a reduction in the highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) energy gap of the blends, evidenced from optical absorption spectra. Classical molecular dynamics simulation studies predicted the probability of enhanced planarity in the polymer backbone following interactions with CNC surfaces. Theoretical results from density functional theory calculations corroborate the experimentally observed reduction of optical bandgap in the blends compared to bare P3HT. The blended composite outperformed the bare P3HT in nitro-group PL sensing tests with a pronounced difference in the reaction kinetics. While the PL quenching dynamics for bare P3HT followed Stern-Volmer kinetics, the P3HT@CNC blended composite exhibited a drastic deviation from the same. This work shows the potential of a functionalized rod-like biopolymer in tuning the optoelectronic properties of a technologically important polymeric organic semiconductor through control of the nanoscale morphology.

17.
Macromol Rapid Commun ; 44(15): e2300129, 2023 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-37232333

RESUMEN

Smart materials that are energy efficient and take up less space are crucial in the development of new technologies. Electrochromic polymers (ECPs) are one such class of materials that actively change their optical behavior in both visible and infrared parts of the electromagnetic spectrum. They show promise in a wide range of applications, from active camouflage to smart displays/windows. The full capabilities of ECPs are still yet to be explored, for while their electrochromic properties are well established, their Infrared (IR) modulation is less reported on. This study addresses the potential of ECPs in active IR modulating devices by optimization of Vapor Phase Polymerized poly(3,4-ethylenedioxythiophene) (PEDOT) thin films via the substitution of its dopant anion. Dynamic ranges denoting emissivity changes between reduced and oxidized states of PEDOT are found across dopants of tosylate, bromide, sulfate, chloride, perchlorate, and nitrate. Relative to the emissivity of reduced (neutral) PEDOT, a range of ±15% is achieved from the doped PEDOT films, and a maximum dynamic range of 0.11 across a 34% change is recorded for PEDOT doped with perchlorate.


Asunto(s)
Percloratos , Polímeros , Aniones
18.
Biotechnol Appl Biochem ; 70(2): 485-501, 2023 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33847399

RESUMEN

Present study is specially designed for the recent advances in biosensors to detect and quantify urea concentration. Urea (carbamide) is an organic compound made up of the carbonyl (C=O) functional group with two -NH2 groups having chemical formula CO (NH2 )2 . In nature, urea is found everywhere as the result of various processes, and in the human body, urea is an end product of nitrogen metabolism. An excessive concentration of urea in the human body is responsible for different critical diseases such as indigestion, acidity, ulcers, cancer, malfunctioning of kidneys, renal failure, urinary tract obstruction, dehydration, shock, burns, gastrointestinal bleeding, and so on. Moreover, below the normal level may cause hepatic failure, nephritic syndrome, cachexia, and so on. As well as in various fields such as fishery, dairy, food preservation, agriculture, and so on, urea is normally found and its detection is necessary. In urea biosensors, enzyme urease (Urs) is used as a bioreceptor element and retains its long last activity is the critical issue in front of the researcher. During recent decades, different nanoparticles (zinc oxide, nickel oxide, iron oxide, titanium dioxide, tin(IV) oxide, etc.), conducting polymer (polyaniline, polypyrrole, etc.), conducting polymer-nanoparticles composites, carbon materials (carbon nanotubes, graphene oxide, reduced graphene oxide graphene), and so on are used in urea biosensors. The main emphasis of the present study is to provide cumulative and comprehensive information about the sensing parameters of urea biosensors based on the materials used for enzyme immobilization. Besides this special task, this review provides a fruitful discussion on the basics of biosensors briefly for new and upcoming researchers. Thus, the present study may act as a gift for a large audience that come from different fields and are working in biosensors research.


Asunto(s)
Técnicas Biosensibles , Nanotubos de Carbono , Humanos , Polímeros/química , Nanotubos de Carbono/química , Urea , Pirroles
19.
Chirality ; 35(2): 110-117, 2023 02.
Artículo en Inglés | MEDLINE | ID: mdl-36513396

RESUMEN

Microfluidic valves based on chemically responsive materials have gained considerable attention in recent years. Herein, a wireless enantio-responsive valve triggered by bipolar electrochemistry combined with chiral recognition is reported. A conducting polymer actuator functionalized with the enantiomers of an inherently chiral oligomer was used as bipolar valve to cover a tube loaded with a dye and immersed in a solution containing chiral analytes. When an electric field is applied, the designed actuator shows a reversible cantilever-type deflection, allowing the release of the dye from the reservoir. The tube can be opened and closed by simply switching the polarity of the system. Qualitative results show the successful release of the colorant, driven by chirality and redox reactions occurring at the bipolar valve. The device works well even in the presence of chemically different chiral analytes in the same solution. These systems open up new possibilities in the field of microfluidics, including also controlled drug delivery applications.


Asunto(s)
Sistemas de Liberación de Medicamentos , Polímeros , Estereoisomerismo , Sistemas de Liberación de Medicamentos/métodos
20.
Mikrochim Acta ; 190(5): 168, 2023 Apr 04.
Artículo en Inglés | MEDLINE | ID: mdl-37012526

RESUMEN

A new electrochemical sensor device has been developed through the modification of a polyaniline-silicon oxide network with carbon black (CB). Enhanced electrical conductivity and antifouling properties have been achieved due to the integration of this cheap nanomaterial into the bulk of the sensor. The structure of the developed material was characterized using Fourier transform infrared spectroscopy, energy-dispersive X-ray spectroscopy, and scanning electron microscopy techniques. Cyclic voltammetry was used to characterize electrochemically the Sonogel-Carbon/Carbon Black-PANI (SNG-C/CB-PANI) sensor device. In addition, differential pulse voltammetry was employed to evaluate the analytical response of the sensor towards sundry chlorophenols, common environmental hazards in aqueous ecosystems. The modified sensor material showed excellent antifouling properties, which led to a better electroanalytical performance than the one displayed with the bare sensor. Notably, a sensitivity of 5.48 × 103 µA mM-1 cm-2 and a limit of detection of 0.83 µM were obtained in the determination of 4-chloro-3-methylphenol (PCMC) at a working potential of 0.78 V (vs. 3 M Ag/AgCl/KCl), along with proficient values of reproducibility and repeatability (relative standard deviation < 3%). Finally, the analysis of PCMC was carried out in multiple validated water samples using the synthesized SNG-C/CB-PANI sensor device, obtaining excellent results of recovery values (97-104%). The synergetic effect of polyaniline and carbon black leads to novel antifouling and electrocatalytic effects that improve the applicability of this sensor in sample analysis versus complex conventional devices.

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