Base Monomer Research Articles

A novel dielectric elastomer with low modulus and fast response

Abstract Dielectric elastomers (DEs) are highly valued in massive fields of actuators and sensors due to their unique advantages of large actuation strain, fast response speed, high energy density and excellent elasticity. The challenge of balancing the elastic modulus, actuation strain and response speed of DE actuators to stably enhance the actuation performance remains a major issue. In this work, a novel DE was prepared by employing polyurethane acrylate (CN9021) as a crosslinker, n-butyl acrylate as a base monomer and 2-ethylhexyl acrylate (2-EHA) as a functional flexible monomer via a UV curing method. The swelling test indicates a reduction of crosslinking density with the increment of 2-EHA concentration in EHA films. As a consequence, the elastic modulus displays a notable decline while the dielectric constant slightly rises, leading to an enhancement of the actuation sensitivity. More specifically, the elastic modulus of our fabricated EHA-1 is only one-third of the commercial VHB-4910. The developed DEs achieve an actuation strain of nearly 150% with low viscoelasticity and mechanical loss resulting in high response speed and broad operating frequency range to the input dynamic voltages. All these actuation performances are superior to VHB-4910. This work provides a promising strategy for developing DEs with balanced performance and superior actuation characteristics.

Surface reaction mechanism of ZSM-5(3T)@NH2-MIL-53(Al) core-shell catalyst for dimethyldichlorosilane synthesis

Dimethyldichlorosilane is one of the most important basic monomers in the silicone industry. It is also can be recovered through by-products disproportionation reactions during synthesis. This paper investigated the reaction mechanism of ZSM-5(3T)@NH2-MIL-53(Al) catalyst, constructed by combining 3T cluster ZSM-5 zeolite and NH2-MIL-53(Al), and the modified AlCl3/ZSM-5(3T)@NH2-MIL-53(Al) catalyst in the disproportionation preparation of (CH3)2SiCl2. The M06-2X/def2-TZVP hybrid functional method from the Minnesota series was used to calculate the energies of all reactants, transition states, and products in the disproportionation preparation of (CH3)2SiCl2 reaction systems for five active sites (before AlCl3 loading) and one active site (after AlCl3 loading), respectively. Additionally, ZPE corrections were applied at the same computational level. The results of structural, energy, vibrational frequency, Intrinsic Reaction Coordinate (IRC)values, bond order, Electron Localization Function (ELF), and Localized Orbital Locator (LOL) analyses were matched. The results indicated that the Lewis acid catalytic active centers obtained after AlCl3 loading enhanced the catalytic performance of AlCl3/ZSM-5(3T)@NH2-MIL-53(Al).

A Fully Saturated Covalent Organic Framework.

We report the design and synthesis of the first aliphatic covalent organic framework (COF), NUS-119, and its subsequent conversion to NUS-120, marking the first fully saturated COF. NUS-119 is built by imine-linkages exhibiting high crystallinity and porosity, achieved by using a Lewis acid as a reaction modulator to circumvent compatibility issues between the Brønsted acid and the strong basic monomer. The structure was successfully solved using 3D microelectron diffraction (microED) techniques. NUS-119 and NUS-120 demonstrated remarkable catalytic performance in base-catalyzed Knoevenagel condensation reactions, exhibiting high conversion rates, excellent size selectivity, and good recyclability. This work advances the understanding of COF materials and paves the way for future research and applications.

Design and Development of Infiltration Resins: From Base Monomer Structure to Resin Properties.

The resin infiltration concept is one of the most widely used minimally invasive restorative techniques in restorative dentistry with the most outstanding therapeutic effect, and it is also one of the key research directions in restorative dentistry. "Infiltration resin" is the specialty restorative material for the technology, which is the key factor to success. The specialized restorative material is commonly known as "infiltrant/infiltration resins" "resins infiltrant" "infiltrant" or "resins," which will be consistently referred to as "infiltration resins" throughout the article. The paper aims to provide a comprehensive overview of infiltration resins by introducing the development of their therapeutic mechanisms, basic components, current challenges, and future trends, Based on existing literature, we analyze and compare how changes in the base monomer's structure and ratio affect the effectiveness of infiltration resins, from the material's structure-effective relationship. After compiling the information, the existing solution strategies have been listed to offer substantial support and guidance for future research endeavors.

A novel Co/Zn-ferrite molecularly imprinted polymer-based electrochemical assay for sensing of gallic acid in plant extracts, wine, and herbal supplement.

In this study, a new molecularly imprinted polymer (MIP)-based sensor platform was developed for the electrochemical determination of gallic acid (GAL) in plant extracts, wine, and herbal supplements. Gallic acid is known for its natural antioxidant properties, which play an important role in preventing cell deterioration that can lead to various diseases. In addition, gallic acid has therapeutic potential due to its anticancer, antiinflammatory, antimicrobial, and neuroprotective properties. Accurate analysis of gallic acid in complex matrices, in mixed samples where different components coexist, is necessary to evaluate the efficacy and safety of this compound. Cobalt ferrite-zinc-dihydro caffeic acid (CFO_Zn_DHCA) nanoparticles, sphere-like in shape and 5 ± 1nm in size, were incorporated into the MIP-based electrochemical sensor design to enhance the active surface area and porosity of the glassy carbon electrode (GCE) surface. The functional monomer chosen for this study was aminophenyl boronic acid (3-APBA). In the GAL/CFO_Zn_DHCA/3-APBA@MIP-GCE sensor, which was developed using photopolymerization (PP), 3-APBA as a functional monomer was designed, and obtained in the presence of basic monomer (HEMA), cross-linker (EGDMA), and initiator (2-hydroxy-2-methyl propiophenone) by keeping it under a UV lamp at 365nm. It aims to detect GAL in real samples such as Punica granatum (pomegranate) peel, Camellia sinensis (green and black tea leaves), wine, and herbal supplements. Morphological and electrochemical characterizations of the designed GAL/CFO_Zn_DHCA/3-APBA@MIP-GCE sensor were carried out using scanning electron microscopy (SEM), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). The linear range for the determination of GAL using the indirect method (5.0mM [Fe(CN)6]-3/-4) was found to be 1.0 × 10-13M-1.0 × 10-12M, and the limit of detection (LOD) and limit of quantification (LOQ) for standard solutions werecalculated as 1.29 × 10-14 and 4.29 × 10-14M, respectively. As a result of the study, the developed MIP-based electrochemical sensor was suitable for detecting GAL with high specificity, selectivity, and sensitivity. Recovery studies were performed to determine the practical applicability of the sensor, and the results were satisfactory. This innovative sensor platform stands out as a reliable and sensitive analytical tool for determining GAL.

Selective apigenin assay in plant extracts and herbal supplement with molecularly imprinted polymer-based electrochemical sensor

This study is the first successful application of a nanomaterial-supported molecularly imprinted polymer (MIP)-based electrochemical sensor for the sensitive and selective determination of apigenin (API), which is a naturally occurring product of the flavone class that is an aglycone of several glycosides. Secondary metabolites are biologically active substances produced by plants in response to various environmental factors. The levels of these compounds can vary depending on factors such as climate, soil conditions and the season in which the plants are grown. Therefore, the analysis of these compounds is essential to properly understand the biological effects of plant extracts and to ensure their safe use. To increase the glassy carbon electrode (GCE) surface's active surface area and porosity, zinc oxide nanoparticles (ZnO NPs) were integrated into the MIP-based electrochemical sensor design. Tryptophan methacrylate (TrpMA) was selected as the functional monomer along with other MIP components such as 2-hydroxyethyl methacrylate (HEMA, basic monomer), 2-hydroxy-2-methylpropiophenone (initiator), and ethylene glycol dimethacrylate (EGDMA, crosslinking agent). The morphological and electrochemical characterizations of the developed API/ZnO NPs/TrpMA@MIP-GCE sensor were performed with scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). The indirect measurement approach via 5.0 mM [Fe(CN)6]3–/4– solution was utilized to determine API in the linear range of 1.0x10−13 M − 1.0x10−12 M. The limit of detection (LOD) and limit of quantification (LOQ) for standard solutions were found to be 2.47x10−14 and 8.23x10−14 M, respectively. In addition, the extraction processes were carried out using ultrasound-assisted extraction (UAE) and maceration (MCR) procedures. For Apium graveolens L., Petroselinum crispum (Mill.) Fuss and herbal supplement, the API recoveries varied from 98.79 % to 102.71 %, with average relative standard deviations (RSD) less than 2.25 % in all three cases. The sensor's successful performance in the presence of components with chemical structures similar to the API was also demonstrated, revealing its unique selectivity.

Investigation of thermal properties and structural characterization of novel boron-containing Schiff base polymers

Three novel Schiff base polymers were synthesized by using the Schiff base monomer obtained using aldehyde containing boric acid and amines containing hydroxyl groups as the starting materials. The polymers were synthesized at the same temperature and using the same amount of oxidizing agent by the oxidative polycondensation method. The characterization of all polymers and monomers was achieved by using Fourier transform infrared spectroscopy (FT-IR), ultraviolet–visible spectroscopy (UV–vis), nuclear magnetic resonance spectroscopy (1H-NMR), liquid chromatography-mass spectrometry (LC–MS), gel permeation chromatography (GPC) and scanning electron microscopy (SEM). The thermal stability of these compounds was studied by employing thermogravimetric analysis (TGA), and thermodynamics parameters such as activation energy (Ea), enthalpy (∆H), entropy (∆S), and Gibbs free energy(∆G) for the decomposition process were calculated using the Flynn–Wall–Ozawa method.

Investigation of electrochemical behaviour and determination of Riociguat with bare GCE and molecularly imprinted polymer-based electrochemical sensor

Pulmonary Arterial Hypertension (PAH) causes death due to ventricular overload and heart failure. Calcium channel blockers, anticoagulants, digoxin and diuretics are the standards of care for PAH. Riociguat (RIO) is an oral soluble guanylate cyclase stimulator approved for the treatment of PAH by World Health Organization (WHO) Group 1 patients. In this study, the electrochemical behavior of RIO was investigated using a bare glassy carbon electrode (GCE). In addition, RIO was determined using GCE and a molecularly imprinted polymer (MIP)-based electrochemical sensor. The MIP-based electrochemical sensor was prepared by photopolymerization of methacrylic acid in the presence of a basic monomer, crosslinker, target molecule, and photoinitiator. The polymer film was characterised by a scanning electron microscope (SEM) and cyclic voltammetry (CV). Under the optimized conditions, the results obtained with GCE and MIP sensor were compared. The analytical performance of GCE and MIP-based electrochemical sensors was evaluated. The linear ranges of RIO were 1.0 × 10–6 – 1.0 × 10–4 M and 1.0 × 10–13 – 1.0 × 10–12 M, with a limit of detection (LOD) of 1.40 × 10–8 M and 2.12 × 10–14 by bare GCE and MIP-based electrochemical sensor using differential pulse voltammetry (DPV), respectively. The results show that the MIP sensor has higher sensitivity than the bare GCE. Both were applied to commercial human serum samples and pharmaceutical dosage forms. The recovery studies were performed, and the recovery% and RSD% results are within the acceptable range. Therefore, the GCE and MIP sensors have good selectivity, accuracy and precision.

Development of ultra-sensitive and selective molecularly imprinted polymer-based electrochemical sensor for L-lactate detection

Lactate detection is important for the food and healthcare industries, and it’s especially important when there’s tissue hypoxia, hepatic illness, bleeding, respiratory failure, or sepsis. A new molecularly imprinted polymer (MIP) based electrochemical sensor was fabricated for differential pulse voltammetric assay of L-lactate (LAC). By using ZIF-8@ZnQ nanoparticles, the number of regions and effective surface area were increased. The polymeric film was obtained using 4 aminobenzoic acid (4-ABA) as a functional monomer, ethylene glycol dimethacrylate (EGDMA) as a cross-linker, 2-hydroxyethyl methacrylate (HEMA) as basic monomers, and 2-hydroxy-2-methylpropiophenone one as initiator. The developed 4-ABA/LAC/ZIF-8@ZnQ@MIP-GCE was morphologically characterised using SEM and electrochemically using electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) measurements. A linear range of 0.1–1.0 pM LAC with a detection limit of 29.9 fM was found. Lastly, the MIP-based electrochemical sensor detected LAC in commercial human serum samples.

A comparative study on the mechanical and antibacterial properties of BPA-free dental resin composites

ObjectiveThe commonly used base monomer utilized in resinous commercial dental restorative products is bis-GMA which is derived from bisphenol-A (BPA) - a well-known compound which may disrupt endocrine functions. To address concerns about its leaching into the oral environment and to optimize the quality of dental composites, a BPA-free alternative base monomer, fluorinated urethane dimethacrylate (FUDMA), was designed by modifying a UDMA monomer system. MethodsNine groups of composites were prepared by mixing the base monomers and TEGDMA in a ratio of 70/30 wt% to which were added silanized glass particles (mean diameter: 0.7 µm) in 3 different volume fractions (40, 45, and 50 vol%). Bis-GMA and UDMA base monomers were used as control groups in the same ratios. Various properties including degree of conversion (DC), flexural strength (FS) and flexural modulus (FM), water sorption (WS), solubility (SL), surface hardness and roughness, and initial adhesion property against S.mutans were investigated. One-way analysis of variance followed by Bonferroni test at α = 0.05 was used to analyze the results. ResultsA significant difference in FS between FUDMA-based composite with 40 vol% filler (120.3 ± 10.4 MPa) and Bis-GMA-based composite with the same filler fraction (105.8 ± 10.0 MPa) was observed but there was no significant difference among other groups. The UDMA based group exhibited the highest WS (1.3 ± 0.3 %). Bis-GMA showed greater initial bacterial adhesion but was not statistically different from the other groups (p = 0.082). SignificanceFUDMA-based resin composites exhibit comparable mechanical and bacterial adhesion properties compared with Bis-GMA and UDMA-based composites. The FUDMA composites show positive outcomes indicating they could be used as substitute composites to Bis-GMA-based composites.

Selective valorization of lignin to C8 phenols over atomically dispersed Ni on basic AlN

Lignin is mainly composed of three basic C9 phenolic monomers, which makes it a formidable challenge to selectively produce C8 phenolic monomers, precursors for the ethylbenzene and styrene, due to intricate C–O and C–C cleavages. Here, we introduce a Ni0.5%/AlN catalyst, featuring atomically dispersed Ni on a basic AlN support. The catalyst yields 52.7 % relative phenolic monomers with an unparalleled selectivity of 58.7 % for C8 phenolic species (Phenol, 4-ethyl, and Phenol, 4-ethyl-2-methoxy). The inherent basic sites within the AlN support crucially facilitate the formation of quinone intermediates, subsequently directed by single-atom Ni into C8 phenolic monomers. The catalyst showcases robust recyclability over five cycles, because of the strong interactions between Ni and AlN support. This study reveals a synergistic interplay between single-atom Ni and the basic support, paving a transformative pathway for the selective valorization of lignin.

Synthesis of carbazole-based Schiff base and fluorescence turn on sensor sensitive to Cr3+ ion: Oxidative and electrochemical polymerization and investigation of electrochromic properties

In this study, a Schiff base monomer (ECBA) was initially synthesized from condensation reaction of 3-amino 9-ethyl carbazole (AEC) with 2,4-dihydroxy benzaldehyde (DHBA). Then, its poly(ECBA-1) polymer was synthesized via oxidative polycondensation in methanol/THF (v/v:4/1) medium by NaOCl oxidant. The structures of the obtained monomer and poly(ECBA-1) were confirmed by 1H NMR, 13C NMR and FT-IR. The optical and electrochemical properties of compounds were examined by UV–Vis, fluorescence spectroscopy and cyclic voltammetry (CV) measurements, respectively. The Highest occupied molecular orbital (HOMO), lowest unoccupied molecular orbital (LUMO) energy levels and electrochemical (E’g) and optical band gap (Eg) values were determined for monomer and polymer compounds by cyclic voltammetry and UV–Vis spectrophotometry. Thermal stabilities of the monomer and poly(ECBA-1) were determined from thermogravimetric-differential thermal analysis (TG-DTA) measurements. The molecular weight distribution and Tg temperature of the poly(ECBA-1) were determined by gel permeation chromatography (GPC) and differential scanning calorimetry (DSC) measurements, respectively. The surface morphologies of the synthesized polymers and copolymer were investigated by scanning electron microscopy (SEM). By fluorescence titration, ECBA was found to be selective towards Cr3+ ion among Ag+, K+, Mn2+, Hg2+, Co2+, Ca2+, Ni2+, Cu2+, Zn2+, Pb2+, Cd2+, Fe3+, Cr3+, Cr+6 ions. The selectivity of Cr3+ion was confirmed by the absence of interference from other competitive cationic species. The limit of detection (LOD) and binding constant (Ka) values for the fluorescent probe were calculated as 6.07 x 10-7 M and 1.25 x 104 M−1, respectively. In addition, homopolymer and copolymer synthesis was carried out on Pet ITO selected as working electrode via electropolymerization method by the synthesized ECBA monomer. Homopolymer synthesis was carried out by Cyclic Voltammetry (CV) method and copolymer synthesis was carried out by batch electrolysis method using EDOT with ECBA monomer. Spectroelectrochemical measurements were taken to investigate the electrochromic properties of the prepared homopolymer poly(ECBA-2) and copolymer (Poly(ECBA-co-EDOT)). The copolymer was found to have a more stable structure than the homopolymer.

Comparative Study of Bis-Schiff Case Containing Conjugated Oligomers Based on Phosphate and Silane Moieties: Investigation of Photophysical and Thermal Properties.

Oligo(azomethine)s bearing phosphate and silane moieties were the subject of an investigation within this study. The initial stage involved the synthesis of two Schiff base monomers, denoted as SCH-1 and SCH-2 (SCHs), each possessing a pair of hydroxyl functional groups. This was achieved through a loss of water between the aldehyde and diamine precursors. Subsequently, the Schiff base entities were subjected to oligomerization through HCl-mediated elimination due to the interaction between the hydroxyl groups of the Schiff bases and the chlorine moieties of dichlorodiethylsilane (Si) or phenyl dichlorophosphate (P). This procedure yielded distinct P-oligo(azomethine) (P1-P, P2-P) and Si-oligo(azomethine) (P1-Si and P2-Si) structures corresponding to each precursor. The molecular structures of the synthesized Schiff base monomers and oligo(azomethine)s were elucidated employing Fourier transform infrared, 1H NMR, and 13C NMR techniques. Thermal properties of the resulting products were assessed by utilizing thermogravimetric analysis (TG-DTG/DTA and DSC) techniques. Scanning electron microscopy (SEM) was employed to acquire high-resolution images and detailed surface information on the samples. Additionally, X-ray diffraction was employed to analyze the phase properties of the solid samples. Furthermore, the optical band gap (E g) values of the resulting P-oligo(azomethine)s and Si-oligo(azomethine)s were determined utilizing UV-vis spectrophotometer. The relatively low band gap values exhibited by the synthesized oligo(azomethine)s were indicative of their potential suitability as semiconductive materials in the realm of electronic and optoelectronic device fabrication. Photoluminescence (PL) measurements disclosed a green emission profile upon excitation by blue light. The oligo(azomethine)s incorporating methoxy groups demonstrated a red shift in comparison to their counterparts with methyl groups. Remarkably, no discernible fluctuations in fluorescence were observed over a 3600 s interval under consistent conditions. This observation underscored the inherent stability of the PL emission across the spectral range of exciting light. Thermal analyses unveiled high thermal stability of the synthesized oligo(azomethine)s, sustaining their structural integrity up to 220 °C. The char % of P-oligo(azomethine)s and Si-oligo(azomethine)s were observed to fall within the range of 29.45-55.47% at 1000 °C. SEM images revealed the absence of pores on the surface of P2-Si, which exhibited the highest limiting oxygen index and thermal heat release index (T HRI) values.

Selective and Sensitive MIP-Based Electrochemical Sensor for the Analytical Determination of Lanreotide

Lanreotide (LAN) is an analog of somatostatin used to treat acromegaly and neuroendocrine tumors. Considering drug toxicity and the lack of sensitive techniques in drug analysis, the development of sensitive analytical methods is of great importance. During this research, a molecular imprinted polymer (MIP) based film [P(HEMA-MAGA)@MIP/GCE] was prepared by photopolymerization technique for electrochemical determination of LAN for the first time. N-methacryloyl-L-glutamic acid (MAGA) and hydroxyethyl methacrylate (HEMA) were used as functional and basic monomers, respectively. The surface alterations were investigated using scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) and the chemical composition of the MIP-based sensor. Theelectrochemical characterization of the modifiedelectrodes was assessed using electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). Using differential pulse voltammetry (DPV) in standard solution and spiked serum sample of LAN, the linear response range for LAN was obtained as 1.0x10 − 14 M – 1.0x10 − 13 M. The limit of detection (LOD) values were 1.76x10 − 15 M and 1.82x10 − 15 M in water and commercial human serum, respectively. The limit of quantitation(LOQ) values for these were 5.85x10 − 15 M and 6.07x10 − 15 M, respectively. The P(HEMA-MAGA)@MIP/GCE sensor also showed excellent recovery in pharmaceutical preparation and commercial human serum form with of 99.37 % and 99.27 %, respectively, with a good RSD value (0.51–0.73), confirming the accuracy and precision of the sensor. As a control, the non-imprinted polymer (NIP) was also prepared to serve in the same way but without the template. The selectivity experiments were conducted using somatostatin (SOM) and octreotide (OC) as potential competitors to demonstrate the selectivity of the proposed sensor against LAN molecules.

Level of BPA contamination in resin composites determines BPA release

ObjectivesResin composites may release bisphenol A (BPA) due to impurities present in the monomers. However, there is a lack of knowledge regarding the leaching characteristics of BPA from resin composites. Therefore, experimental resin composites were prepared with known amounts of BPA. The objective of this study was (1) to determine which amount of BPA initially present in the material leaches out in the short term and, (2) how this release is influenced by the resin composition. MethodsBPA (0, 0.001, 0.01, or 0.1 wt%) was added to experimental resin composites containing 60 mol% BisGMA, BisEMA(3), or UDMA, respectively, as base monomer and 40 mol% TEGDMA as diluent monomer. Polymerized samples (n = 5) were immersed at 37 °C for 7 days in 1 mL of water, which was collected and refreshed daily. BPA release was quantified with UPLC-MS/MS after derivatization with pyridine-3-sulfonyl chloride. ResultsBetween 0.47 to 0.67 mol% of the originally added BPA eluted from the resin composites after 7 days. Similar elution trends were observed irrespective of the base monomer. Two-way ANOVA showed a significant effect of the base monomer on BPA release, but the differences were small and not consistent. SignificanceThe released amount of BPA was directly proportional to the quantity of BPA present in the resin composite as an impurity. BPA release was mainly diffusion-based, while polymer composition seemed to play a minor role. Our results underscore the importance for manufacturers only to use monomers of the highest purity in dental resin composites to avoid unnecessary BPA exposure in patients.

Multi-material embedded 3D printing for one-step manufacturing of multifunctional components in soft robotics

Developing a simple and effective preparation method for integrating functional components into highly flexible and multifunctional soft robotics is challenging. Here, we report a novel method for the integrated manufacturing of silicone-based multifunctional soft robotics components based on multi-material embedded 3D printing. By directly printing diluted platinum catalyst ink within a removable silicone oil matrix, which consists of a base monomer and crosslinker, we achieve one-step and time-unrestricted manufacturing of complex spatial structures (e.g., diamond frame, DNA double-helix structure, tubes, ears). The formed volume presents a high ratio (up to 25) to ink consumption volume. Meanwhile, printing materials and parameters are investigated for strong filament fusion and freeform fabrication of complex structures with high fidelity. Furthermore, a compliant robotic fishtail and pneumatic humanoid hand with seamlessly integrated strain sensors are designed and fabricated using this process. These components demonstrate effective execution, while the integrated sensors exhibit excellent linearity (0.99), repeatability, and stability, further demonstrating the feasibility and superiority of the proposed method for manufacturing soft robotics. These results confirm the enormous potential of this progressive method for flexibility, functionality, and integrated manufacturing of soft robotics.

Development and Fabrication of a Molecularly Imprinted Polymer-Based Electroanalytical Sensor for the Determination of Acyclovir.

Acyclovir (ACV), a synthetic nucleoside derivative of purine, is one of the most potent antiviral medications recommended in the specific management of varicella-zoster and herpes simplex viruses. The molecularly imprinted polymer (MIP) was utilized to create an effective and specific electrochemical sensor using a straightforward photopolymerization process to determine ACV. The polymeric thin coating was developed using the template molecule ACV, a functional monomer acrylamide, a basic monomer 2-hydroxyethyl methacrylate, a cross-linker ethylene glycol dimethacrylate, and a photoinitiator 2-hydroxy-2-methyl propiophenone on the exterior of the glassy carbon electrode (GCE). Scanning electron microscopy, attenuated total reflectance-Fourier transform infrared spectroscopy, electrochemical impedance spectroscopy, and cyclic voltammetry were employed for the purpose of characterizing the constructed sensor (AM-ACV@MIP/GCE). Differential pulse voltammetry and a 5 mM ferrocyanide/ferricyanide ([Fe(CN)6]3-/4-) redox reagent were used to detect the ACV binding to the specific cavities on MIP. The study involves density functional theory (DFT) calculations, which were conducted to investigate template-functional monomer interactions thoroughly, calculate template-functional monomer interaction energies, and determine the optimal template/functional monomer ratio. DFT calculations were performed using Becke's three-parameter hybrid functional with the Lee-Yang-Parr correlation functional (B3LYP) method and 6-31G(d,p) basis set. The sensor exhibits linear performance throughout the concentration region 1 × 10-11 to 1 × 10-10 M, and the limit of detection and limit of quantification were 7.15 × 10-13 M and 2.38 × 10-12 M, respectively. For the electrochemical study of ACV, the sensor demonstrated high accuracy, precision, robustness, and a short detection time. Furthermore, the developed electrochemical sensor exhibited exceptional recovery in tablet dosage form and commercial human blood samples, with recoveries of 99.40 and 100.44%, respectively. The findings showed that the AM-ACV@MIP/GCE sensor would effectively be used to directly assess pharmaceuticals from actual specimens and would particularly detect ACV compared to structurally similar pharmaceutical compounds.

Development and thermo-mechanical characterization of cyanoacrylate-based tissue adhesives

Tissue adhesives are crucial in current medical practice, facilitating the healing process in traumatic lacerations and surgical incisions. This work aims to develop and characterize tissue adhesives based on cyanoacrylate-based n-butyl and octyl blends. The characterization of three different formulations was achieved through Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC). FTIR spectra were obtained between 200 and 4000 cm−1, and the results indicated the presence of specific functional groups, specifically for the base monomers of the formulas between 1000 and 1200 cm−1. The samples started to degrade around 160 °C and were completely degraded between 200 and 250 °C. Viscosity analysis showed that the shear rate range was from 300 to 1 s−1, while the temperature varied between 20 and 37 °C. Dynamic Mechanical Thermo-Analysis (DMTA) showed similar storage and loss modulus under a temperature range of 0–80 °C. In contrast, a commercial standard sample, utilized as a comparison standard, showed the lowest values, about 25% less than other samples. Oscillatory rheology performed under 37 °C and varying the deformation amplitude (0–100%) with an oscillation frequency of 5 rad/s allowed a comparison between the samples evaluated and the results from DMTA testing. Mechanical characterization was achieved through a comparison between these results and the correspondent results of mechanical testing as per ASTM standards applicable to tissue adhesives—F2258-05, F2255-05, F2256-05, and F2458-05. They suggest the utilization of a viscous n-butyl and 2-octyl cyanoacrylate-based blend, allying a better degree of biocompatibility with adequate mechanical performance.

A novel low shrinkage dimethacrylate monomer as an alternative to BisGMA for adhesive and resin-based composite applications.

The aim of this study was to develop a mixture of dimethacrylate isomers (PG6EMA) as a potential monomer for dental adhesives and composites. PG6EMA was synthesized de novo and characterized in the presence of ethanol (3%, 6% or 9%). BisGMA/TEGDMA (BTEG, 50/50 wt.%) was used as the resin control. Composites were formulated with 60 wt.% of either PG6EMA or BisGMA (40 wt.% TEGDMA and 70 wt.% filler). DMPA (0.2 wt.%) and DPI-PF6 (0.4 wt.%) were added as photoinitiators, irradiated with a mercury arc lamp (320-500 nm, 500 mW/cm2; Acticure). All materials were tested for polymerization kinetics (near-infrared), viscosity (η) and storage modulus (G', oscillatory rheometry). The composites were further characterized for water sorption/solubility, wet/dry flexural strength/modulus and polymerization stress. Data were analyzed with one-way ANOVA/Tukey's test (α = 0.05). The PG6EMA resins showed lower rates of polymerization compared with BTEG (p = 0.001) but high degrees of conversion (p = 0.002). Solvent concentration did not affect RPMAX but the 6% and 9% mixtures showed higher final DC, likely due to reduced viscosity. PG6EMA had much higher viscosity than BTEG (p <0.001) and lower G' (p = 0.003). Composites modified with PG6EMA have slower polymerization rates (p = 0.001) but higher final DC (p = 0.04) than the control. PG6EMA/TEGDMA showed lower dry/wet flexural strength and comparable dry modulus. The PG6EMA/TEGDMA composite showed a 18.4% polymerization stress reduction compared to the BTEG composite. Both base monomers had similar WS/SL and G'. Within its limitations, this study demonstrated that the newly synthesized PG6EMA was a viable alternative to BisGMA in dental composites.

Amide-Containing Bottlebrushes via Continuous-Flow Photoiniferter Reversible Addition-Fragmentation Chain Transfer Polymerization: Micellization Behavior.

Herein, a series of ternary amphiphilic amide-containing bottlebrushes were synthesized by photoiniferter (PI-RAFT) polymerization of macromonomers in continuous-flow mode using trithiocarbonate as a chain transfer agent. Visible light-mediated polymerization of macromonomers under mild conditions enabled the preparation of thermoresponsive copolymers with low dispersity and high yields in a very short time, which is not typical for the classical reversible addition-fragmentation chain transfer process. Methoxy oligo(ethylene glycol) methacrylate and alkoxy(C12-C14) oligo(ethylene glycol) methacrylate were used as the basic monomers providing amphiphilic and thermoresponsive properties. The study investigated how modifying comonomers, acrylamide (AAm), methacrylamide (MAAm), and N-methylacrylamide (-MeAAm) affect the features of bottlebrush micelle formation, their critical micelle concentration, and loading capacity for pyrene, a hydrophobic drug model. The results showed that the process is scalable and can produce tens of grams of pure copolymer per day. The unmodified copolymer formed unimolecular micelles at temperatures below the LCST in aqueous solutions, as revealed by DLS and SLS data. The incorporation of AAm, MAAm, and N-MeAAm units resulted in an increase in micelle aggregation numbers. The resulting bottlebrushes formed uni- or bimolecular micelles at extremely low concentrations. These micelles possess a high capacity for loading pyrene, making them a promising choice for targeted drug delivery.