Determination of the relative sensitivity of polyaniline inks and films to deprotonation by ammonia using UV–Vis spectroscopy

The deprotonation behavior of conducting polymers such as polyaniline (PANI) is an important functional parameter in the design of novel printed electronic devices, particularly for sensors and energy storage. PANI can be fabricated into films from precursor liquid-processable 'ink' formulations. The effective determination and comparison of the deprotonation behavior of such inks is critical to understanding their subsequent functional performance. While protonation can be measured by titration with protonating and deprotonating agents using UV-vis spectroscopy, comparative analysis has proven challenging due to complexities in the measurement of polymer concentration and consequent lack of comparability. This work introduced a coherent approach to establishing the arbitrary concentration of PANI ink formulations. Dodecylbenzene sulfonic acid (DBSA)-micellar doped PANI nanoparticles suspended in sodium dodecyl sulfate were prepared using various monomer, oxidant, and dopant ratios, titrated with ammonia and analyzed using UV-vis spectroscopy. Isosbestic points unaffected by doping or protonation state were used to establish arbitrary polymer concentration. Similar titrations on films prepared from these formulations were performed using ammonia in the gas phase and were based on calculations of deposited mass. Parameters such as a 'doping capacity', and their relative sensitivity to ammonia could be determined, which could in turn be related to the physical and chemical compositions of the resulting inks and films. The developed methodology has the potential to be a simple and convenient means with which to compare and optimize the functional deprotonation behavior of conducting polymer inks and films for device development and production optimization

Synthesis of aromatic poly(pyridinium salt)s and their electrochromic properties

Synthesis of a series of new conjugated electrochromic polymeric pyridinium salts containing main-chain triphenylamine and their electrochromic properties were demonstrated. All polymers exhibit intense UV absorptions at 336-338 nm in DMF and 340-343 nm in thin film form and fluorescence centered at 410-438 nm in DMF and 460-461 nm in thin film form. The electrochromic properties of the films were investigated by electrochemical and spectroelectrochemical methods. Reversible redox signals with stable electrochromic characteristics were obtained via cyclic voltammetry. The electrochromic properties of the polymers remain highly stable after 50 cycles between 0 and 1.2 V

Polymerization and biosensor application of water soluble peptide-SNS type monomer conjugates

A simple and efficient approach for the preparation of a biosensing platform was developed based on newly designed peptide-SNS type monomer conjugates. The approach involves the electrochemical polymerization of the peptide-SNS type monomer on the electrode surface. To synthesize the peptide bearing monomers, the SNS-type monomer having a carboxylic acid functional group was anchored to the C-terminal of the peptide by solid phase peptide synthesis via coupling reagents. Utilization of peptides to increase the solubility of the monomers was first investigated in this report. The obtained monomers, soluble in water, were fully characterized by spectral analyses and utilized as matrices for biomolecule attachment. Polymerization of monomers in water has the potential to provide an alternative process for the electrochemical preparation of the polymers in aqueous media, without using any organic solvent. Under the optimized conditions, the biosensor responded to the target analyte, glucose, in a strikingly selective and sensitive manner, and showed promising feasibility for the quantitative analysis of glucose in beverages

D-A-D type functional conducting polymer: Development of its electrochromic properties and laccase biosensor

Makale (Early Access)Herein, a novel D-A-D type monomer that contains hexylthiophene as the donor and benzo[c][1,2,5]thiadiazole as the acceptor has been electropolymerized successfully to yield P(DTFBT) and its electrochromic properties and performance in amperometric biosensors have been investigated. The polymer shows great electrochemical features with low band gap and multichromic properties. Additionally, after polymer modification, laccase was immobilized on a modified electrode surfaces for catechol sensing. Biosensor optimization values, cycle number, enzyme amount, pH and also interfering effect of some possible compounds were investigated. With optimum values, analytical characterization of the sensor was determined. Kmapp, LOD and sensitivity values were estimated as 0.11 mM, 0.014 mM and 166.74 mu A/(mM cm(2)), respectively. The experimental results revealed that the sensor shows satisfactory accuracy and confirms the proposed sensor has a potential candidate for catechol quantification.Türkiye Bilimsel ve Teknolojik Araştırma Kurumu (TÜBITAK

A new ethanol biosensor based on polyfluorene-g-poly(ethylene glycol) and multiwalled carbon nanotubes

Functionalization of the conjugated polymers has gained considerable interest in the biomedical engineering and biosensing applications as distinct properties can be imparted to the corresponding pristine analogues. In the present work, we report a novel sensing platform for the quantification of ethanol through a macromolecular design involving polyfluorene-g-poly(ethylene glycol) (PF-g-PEG) and multiwalled carbon nanotubes (MWCNTs). First, poly(ethylene glycol) with fluorene functionality (PEG-FL) was synthesized with a one-step procedure and characterized. The nanotube modified electrodes were then used as working electrodes for the electropolymerization of PEG-FL macromonomer to form PF-g-PEG films on the electrode surface. Finally, alcohol oxidase enzyme was immobilized on the modified surfaces. Similar devices without MWCNTs or PF-g-PEG were prepared and compared. Sensor properties for selective ethanol detection were investigated and it was found that PF-g-PEG modified MWCNTs exhibited the highest sensing ability. The potential practical application of the fabricated biosensor is demonstrated in alcoholic drinks for the analysis of ethanol contents