N-hydroxymethyl Acrylamide Research Articles

Double Network Gel Electrolyte with High Ionic Conductivity and Mechanical Strength for Zinc-Ion Batteries.

Gel electrolytes hold promise for stabilizing zinc-ion batteries (ZIBs), but achieving both high ionic conductivity and strong mechanical properties remains challenging. This work presents a double network gel electrolyte based on poly(N-hydroxymethyl acrylamide) (PNMA) and sodium alginate (SA), overcoming this trade-off. The PNMA network provides mechanical strength and water retention, while the SA network facilitates rapid zinc-ion (Zn2+) diffusion through tailored solvation. This double network gel exhibits a tensile strength of up to 838 kPa, significantly higher than previous reports. The SA network provides ion channels for rapid transport of hydrated Zn2+, enhancing the ionic conductivity to a ground-breaking 33.1 mS cm-1. This value is even higher than the liquid electrolytes. The growth of Zn dendrites is also suppressed due to the mechanical constraint and rapid ion conduction. In symmetrical cells, the PNMA/SA gel demonstrates exceptional cycling stability (>2000 h). Characterizations show this is because of reduced free water amount, hindering cathode material dissolution. The full cells with sodium vanadate cathode manifest a high capacity (364.8 mA h g-1 at 0.5 A g-1) and excellent capacity retention (83% after 2500 cycles at 10 A g-1). This double network design offers a way to achieve high-performance and stable ZIBs.

Molecular docking and molecular dynamics study of 3-hydroxybutyrate with polymers for diabetic ketoacidosis-targeted molecularly imprinted polymers

Context: Molecularly imprinted polymers (MIPs) are promising materials with tailored binding sites that can selectively recognize and bind target molecules. The combined approach of molecular docking and molecular dynamics (MD) simulation provides valuable insights into the interactions between 3-hydroxybutyrate (3HB) and the designed MIPs, shedding light on the intricate details of their binding mechanisms. This information is crucial for designing MIPs with high selectivity and affinity for 3HB, which is a key biomarker of diabetic ketoacidosis (DKA). Aims: To examine the interactions and dynamic behavior of 3HB in a complex with ten polymers by employing molecular docking and MD simulations. Methods: Initially, molecular docking was employed to predict the binding orientations and affinities of the 3HB molecule within the active sites of the polymers. Subsequently, molecular dynamics simulation was utilized to explore the dynamic behavior, stability, and interactions within these complexes for 100 ns. Metabolic and toxicological properties of 3HB using SwissADME were also predicted. Results: N-(hydroxymethyl)acrylamide (NHMAm), hydroxyethyl methacrylate (HEMA), itaconic acid (ITA), and N-[tris(hydroxymethyl)methyl]acrylamide (TrisNHMAm) displayed the strongest interactions with 3HB, with binding affinities of -2.64, 2.523, 2.469, and 2.305 kcal/mol, respectively. Various kinds of molecular interactions influence ligand-polymer binding in a variety of ways, as illustrated by the four polymers with the lowest binding affinities. In molecular dynamics, 4-vinylpyridine (4VP), N,N-dimethylacylamide (DMAm), N-(hydroxyethyl)acrylamide (NHEAm), and hydroxyethyl methacrylate (HEMA) suggest a strong stable complex with 3HB with an overall ΔTOTAL of -0.56, -0.35, -0.32, and -0.27 kcal/mol, respectively. The ADME prediction indicated that 3HB has favorable pharmacokinetic properties. Conclusions: HEMA shows the ability to interact well with 3HB both by molecular docking and molecular dynamics.

Synergic enhancement of hydrogel upon multi-level hydrogen bonds via macromolecular design for dual-mode electronic skin

Acrylamide (AM) derivative polymer hydrogels were widely used due to their excellent mechanical performances and the ease to be further functionalized, while there are significant differences in both microstructure and performances along with the variation of substituent groups. So far, the intrinsic reason for this is never revealed. In this paper, double network hydrogels with three AM derivative monomers as the first polymer network: AM, N,N-dimethylacrylamide (DMAA) and N-hydroxymethylacrylamide (NMA), and methyl cellulose (MC) as the second network, were prepared. Compared with PAM based hydrogel, the elasticity and toughness of PDMAA based hydrogel increased by two times. The results from molecular dynamics simulation, FT-IR and XRD demonstrate that intermolecular force among polymer networks in hydrogels increased with AM derivative polymers achieved from primary amine to tertiary amine (DMAA), stemmed from the variation of substituent groups on N atom of AM derivative monomers. The PDMAA based hydrogel was finally employed to construct a dual-mode electronic skin, in a wearable sensor with the fastest response of 0.1 s and a self-powered device with a capacitance of 438.27 mF/cm2. This work provided an in-depth understanding for the optimization of PAM based hydrogels and a novel way for the construction of flexible devices.

Excellent interfacial compatibility of phase change capsules/polyurethane foam with enhanced mechanical and thermal insulation properties for thermal energy storage

The incorporation of phase change microcapsule (microPCMs) substantially augmented the temperature regulation capacity of foams, endowing it with outstanding application potential in numerous industrial domains. However, interfacial compatibility issues between the capsule and the substrate always exist and affect foam performance. In this study, a milli-meter macrocapsule (macroPCMs) containing microPCMs was prepared using calcium alginate gel as the second layer wall to physically improve the interfacial compatibility. And poly (N-hydroxymethyl acrylamide) was in situ polymerized in the gel layer and provided active alcohol hydroxyl groups to form chemical grafting with the polyurethane raw materials, which further chemically improved the interfacial compatibility. These measures created a significantly improved foam microstructure and a greatly increased foaming capacity, which thus endow the composite foam with excellent thermal insulation performance and mechanical strength. Compared with conventional microPCMs-based foam, the foaming capacity of the macroPCMs-based foam increased by 40 folds, the temperature regulation duration increased by 7 folds, and the mechanical performance increased by 3 folds. Moreover, the insulated incubator fabricated with the macroPCMs-based foam exhibited two-fold greater thermal insulation efficiency than conventional models containing internal ice incubator, which validated the potential of employing macroPCMs-based polyurethane foam in cold chain logistics applications.

High tensile properties, wide temperature tolerance, and DLP-printable eutectogels for microarrays wearable strain sensors

Due to good stretchability, conductive gels have significant advantages in the field of manufacturing wearable flexible electronic devices. However, hydrogel-based and ionogel-based conductive materials reported in previous studies are prone to solvent evaporation and leakage, which would seriously affect the gel electromechanical performance in extreme working environments. In addition, how to manufacture gel-based flexible devices with complex structures is also a significant challenge in this field. Based on this, a photocurable 3D-printed eutectogel system was designed in this work. The precursor solution was composed of N-hydroxymethyl acrylamide (NAM), hydroxyethyl methacrylate (HEMA), and DES solvents. The prepared eutectogel had excellent comprehensive properties, such as good transparency (>80 % in the visible region), high tensile performance (up to 648 %), strong mechanical strength (breaking strength up to 938 kPa), electrical conductivity (up to 78 mS/m at 25 ℃), environmental tolerance (-80 ℃ − 60 ℃), and so on. In addition, flexible wearable devices with complex microstructures can be constructed efficiently by DLP printing technology. In the low-pressure detection range (0–––2.5 kPa), the sensitivity of the printed eutectogel-based microarray was 8.78 times higher than that of the block or sheet gel structure, and various weak deformation signals can be timely and accurately detected. Therefore, the combination of photo-cured 3D printing and eutectic gels will provide new possibilities for the development and promotion of intelligent, flexible wearable devices.

Preparation of flame retardant and anti-dripping PET fabric based on sodium copper chlorophyllin dyeing, UV grafting and phosphorylation

The traditional flame retardant polyester fiber containing phosphorus has serious melt droplet phenomenon, and its flame retardancy will be greatly decreased after dyeing, which seriously restricts its wide application. To address the issue, PET fibers were dyed by sodium copper chlorophyllin (SCC) at high temperature to prepare dyed PET fibers (DPET) with dyeing and anti-dripping properties. To further improve the flame retardancy of DPET, N-hydroxymethylacrylamide (NMA) was UV-grafted to DPET (DPET-g-NMA), which was then chemically modified by diammonium hydrogen phosphate (DAP) through high-temperature esterification reaction to obtain flame retardant PET fibers (FR-PET). The results showed that the char-forming ability of FR-PET was higher than that of DPET, and the melt droplet was effectively suppressed. In addition, the heat release rate (HRR), the peak of heat release rate (PHRR), and the total smoke production (TSP) of FR-PET were all significantly reduced, showing good flame retardancy. This work developed a simple and green strategy to improve the flame retardancy and anti-dripping performance of PET fiber without subsequent dyeing, showing great application prospects.

Magnetic nanoparticle-facilitated rapid mass production of high affinity polymeric materials (nanoMIPs) for protein recognition and biosensing.

Molecularly imprinted polymers (MIPs) have been investigated extensively for broad applications in diagnostics, imaging and therapeutics due to their antibody-like specificity, high stability, and low-cost and rapid production when compared with biological antibodies. Yet, their wide-scale adoption and commercial viability are limited due to low yields and relatively lengthy preparations of current methods. We report the novel application of protein-functionalised magnetic nanoparticles (MNPs) to enable the rapid mass production of nanoMIPs for protein recognition. An aldehyde-functionalised MNP (MNP@CHO) precursor was synthesised using a one-pot microwave method in less than 20 minutes, resulting in 330 mg yield for a 30 mL reaction volume. The MNP@CHO precursor (10 mg) was subsequently functionalised with 600 μg of a target template protein, giving MNP@protein. In the presence of an N-hydroxymethylacrylamide (NHMA) functional monomer and N,N'-methylene bisacrylamide as a crosslinker, the MNP@protein particles served as nucleants for the mass production of nanoMIPs in a 20-30 minute synthesis process. Subsequently, the nanoMIPs could be harvested with sonication and then retrieved using a magnet, leaving the MNP@protein particles to be recycled and re-used at least 5 times for further nanoMIP production cycles. In general, 10 mg of MNP@protein produced 10 mg of nanoMIP with a 20% decrease in the yield over the 5 synthesis cycles. For the bovine haemoglobin nanoMIP, the KD was determined to be 3.47 × 10-11 M, a binding affinity rivalling values found for monoclonal antibodies. We also demonstrate that the methodology is generic by producing high-affinity nanoMIPs for other proteins including albumin, lysozyme and SARS-CoV-2 recombinant protein. We therefore present a facile route to produce nanoMIPs in large industrially relevant quantities (hundreds of mg) and at short timescales (within a day). Our method offers realistic opportunities for the industry to adopt such materials as an antibody replacement technology in diagnostics, biological extraction and therapeutics.

Nitrogen-doped lychee-like saccharide-based carbon microspheres with high-performance microwave absorption

The reasonable design of multiple interfaces and heteroatom doping can substantially improve the wave-absorbing performance of electromagnetic wave (EMW) absorbing materials. As the carbon source of biomass, the carbon material with abundant oxygen-containing groups on the surface can be obtained by hydrothermal method, which is conducive to modification and design of the morphology. In addition, N-hydroxymethyl acrylamide contains rich N atoms and has good water solubility, which can be well combined with sugar to prepare high-performance wave-absorbing materials. In this study, D-xylose and glucose were used as carbon sources, water was used as solvent, N-hydroxymethyl acrylamide was added, and nitrogen-doped lychee-like saccharide-based carbon microspheres (LSCMs) were obtained by hydrothermal synthesis and high-temperature carbonization. LSCMs-2 with good EMW attenuation capability and impedance matching performance was obtained by controlling the proportion of different raw materials. Under the optimal filling conditions, the EMW absorber is only 2 mm thick and achieves a minimum reflection loss (RL min) of −47.44 dB at 13.84 GHz with an effective absorption bandwidth (EAB) of 12.24–17.36 GHz (5.12 GHz). The excellent EMW attenuation performance is mainly attributed to dipole polarization and interface polarization in the LSCMs. This research offers a new green synthesis route for the preparation of EMW absorbers with wider bandwidth, thinner thickness and better absorption performance.

Controllable synthesis of 3D superhydrophilic Cd(II) ion-imprinted polymer microspheres based on OV-POSS and bifunctional monomers synergy with superior selectivity for Cd(II) adsorption

Novel 3D porous Cd(II) ion-imprinted polymer (Cd(II)-IIP) microspheres based on octavinyl polyhedral oligomeric silsesquioxane (OV-POSS) were prepared by reversible addition-fragmentation chain transfer (RAFT) polymerization technique combined with the synergistic effect of N-hydroxymethylacrylamide (NMA) and 1-vinylimidazole (1-VI) as bifunctional monomers. RAFT polymerization could achieve a controllable synthesis of polymer networks on OV-POSS. The structure, composition and properties of Cd(II)-IIP were systematically investigated by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, atomic force microscope, water contact angle and thermogravimetric analysis. The results showed that the adsorbent, with a water contact angle of 0 ° and superhydrophilicity, has a high potential for application in aqueous phase systems. Different parameters influencing the sorption performance of Cd(II)-IIP, such as OV-POSS ratio, functional monomers ratio, adsorbent dosage, pH and adsorption time were optimized. Under optimal conditions, the maximum adsorption amount of Cd(II)-IIP for Cd(II) was 80.21 mg/g, and the adsorption equilibrium state could be reached within 40 min. The sorption kinetics proved that the sorption was chemisorption and the rate-limiting step was intraparticle diffusion. Thermodynamic studies showed that Cd(II) sorption was a spontaneous endothermic process. Importantly, XPS analysis, density functional theory (DFT) and frontier molecular orbital (FMO) theory calculations showed that the sorption of Cd(II)-IIP was attributed to the coordination of O and N atoms with Cd(II) on NMA and1-VI, respectively. Actual water sample analysis results indicated that Cd(II)-IIP was an adsorbent of great application potential.

Evaluation of a novel N-(Hydroxymethyl) acrylamide polymer gel dosimeter formulation with organic glucose additive for radiotherapy

In this study, the first evaluation of organic sensitizer material on N-(Hydroxymethyl) acrylamide (NHMA) polymer gel dosimeter was presented. A novel tissue-equivalent polymer gel formula composed of NHMA containing different concentrations of organic glucose additive (GL-NHMA) was developed and evaluated for its potential use to measure 3D dose distributions to compare with treatment planning system. The new polymers of GL-NHMA were irradiated using a linear accelerator (LINAC) with a megavolt X-ray photon beam over a dose range of 2–20 Gy, energies of 6, 10, and 15 MV, and dose rates of 50, 200, and 500 cGy/min. The samples were evaluated using 0.5 T nuclear magnetic resonance (NMR) technique in terms of spin-spin relaxation rate (R2). Comparing with the conventional NHMA composition (i.e., 0 wt% GL concentration), the sensitivity of the GL-NHAM was improved by 53%, 68%, 89%, and 115% with 10, 15, 20, and 25 wt% GL, respectively, with an excellent linear dose response up to 8 Gy. There were no observable effects on the R2 dose response induced by varying the dose rate, photon energy, and irradiation temperature. The polymerization was stable after irradiation for a period of 10 days. Additionally, the R2 values decreased with increasing the scanning temperature. The dosimeter is water equivalent and is energy-independent from 0.1 to 20 MeV when considering the optimum composition. The gel dosimetry accuracy was evaluated in this study by calculating the overall uncertainty and found to be 4.64% (2σ, 95% confidence level). The GL additive acts as an excellent organic sensitizer in the GL-NHMA system, suggesting that this improved polymer formulation may be a useful tool for measuring dose distributions in radiotherapy at clinically relevant dose levels.

Synthesis and evaluation of phenolic capsaicin-derived self-polymers for antibacterial activity

Capsaicin, as a low-toxic antibacterial bioactive substance, is recognized as an environmentally friendly antifouling agent. To obtain a naturally derived antifouling agent with stronger antibacterial ability, capsaicin-derived self-polymers (labeled POHABA, PPHABA, PAHMA, and PAMTHBA) containing phenols (catechol, hydroquinone, resorcinol, phloroglucinol) and N-hydroxymethyl acrylamide were synthesized by precipitation polymerization, which was uniform spheroids with folded surfaces (diameter 0.6–1.6 µm, except PAMTHBA diameter 200–400 nm). The antibacterial activity assay showed that they had a significant inhibitory effect on E. coli and S. aureus (MIC: 0.4 mg/mL against E. coli and 0.8 mg/mL against S. aureus; antibacterial rate: 99.99 % for E. coli and 98.18 % for S. aureus), which was related to the content of phenolic hydroxyl on the surface of the microspheres by comparison with the semi-quantitative analysis of EDS and XPS spectra. The antibacterial activity of self-polymers was significantly higher than that of the monomers, mainly because there were more and more uniform hydroxyl groups on the surface of polymer microspheres. These results provide a theoretical basis for capsaicin-derived self-polymers to be applied to environmentally friendly antifouling agents.

Synthesis of poly(styrene-N-hydroxymethyl acrylamide) microspheres and their application in patterned photonic crystals

In order to achieve bright and durable structural colors, the poly(styrene-N-hydroxymethyl acrylamide) nanospheres with self-crosslinking property were used as structural units to construct patterned photonic crystals. In this article, we thoroughly explore the effect of synthesis factors on particle sizes and monodispersity of poly(styrene-N-hydroxymethyl acrylamide) nanospheres, with the characterization of the performance of prepared poly(styrene-N-hydroxymethyl acrylamide) nanospheres. Then the color effects and durability of structural colors produced from poly(styrene-N-hydroxymethyl acrylamide) photonic crystals were characterized and evaluated. The results showed that the monodisperse poly(styrene-N-hydroxymethyl acrylamide) nanospheres with particle sizes ranging between about 200∼320 nm could be synthesized. The prepared poly(styrene-N-hydroxymethyl acrylamide) nanospheres exhibit typical core-shell structure, in which the hydrophobic polystyrene domain is mainly located on the core, and there is a thin shell mainly rich in hydrophilic Poly(N-hydroxymethyl acrylamide) covering the polystyrene core. Moreover, the poly(styrene-N-hydroxymethyl acrylamide) nanospheres have self-crosslinking properties, which could be confirmed by the thermogravimetric curve. Furthermore, the photonic crystals constructed by prepared poly(styrene-N-hydroxymethyl acrylamide) nanospheres still present vivid and durable structural colors after friction, bending, washing and soaking tests. Specifically, the patterned photonic crystals can be constructed on photo paper, plastic board and fabrics, and the resultant structural colors present significantly iridescent effects. The research results can provide strategic support for the practical application of photonic crystals with structural colors.

β-Cyclodextrin-Based Ultrahigh Stretchable, Flexible, Electro- and Pressure-Responsive, Adhesive, Transparent Hydrogel as Motion Sensor.

In the present work, a multiple-stimuli-responsive hydrogel has been synthesized via polymerization of acrylamide (AAm) and N-hydroxy methyl acrylamide (HMAm) on β-cyclodextrin (β-CD). The synthesized hydrogel β-CD-g-(pAAm/pHMAm) exhibited various striking features like ultrahigh stretchability (>6000%), flexibility, stab resistivity, self-recoverability, electroresponsiveness, pressure-responsiveness, adhesiveness, and high transparency (>90%). Besides, the hydrogel has demonstrated enhanced biocompatibility, UV resistance, and thermoresponsive shape memory behaviors. On the basis of these attractive characteristics of the hydrogel, a flexible pressure sensor for the real-time monitoring of human motion with superior biocompatibility and transparency was fabricated. Moreover, due to the nanofibrillar surface morphology of the β-CD-g-(pAAm/pHMAm) hydrogel, the sensor based on the gel exhibited high sensitivity (0.053 kPa-1 for 0-3.3 kPa). The flexible sensor demonstrates very fast response time (130 ms-210 ms) with adequate stability (5000 cycles). Interestingly, the sensor can rapidly sense both robust (index finger and wrist) motions as well as tiny (swallowing and phonation) physiological actions. In addition, this adhesive hydrogel patch also acts as a potential carrier for the sustained topical release of (∼80.8% in 48 h) the antibiotic drug gentamicin sulfate.

Application of thymine-based nucleobase-modified acrylamide as a functional co-monomer in electropolymerised thin-film molecularly imprinted polymer (MIP) for selective protein (haemoglobin) binding.

Molecularly imprinted polymers (MIPs) are fast becoming alternatives to biological recognition materials, offering robustness and the ability to work in extreme environments. Here, a modified thymine-based nucleobase, with acrylamide at the 5-postion (AA-dT) was used as a co-monomer in the synthesis of a thin-film electropolymerised MIP system for the molecular recognition of the protein haemoglobin. The AA-dT co-monomer incorporated into a N-hydroxymethylacrylamide (NHMAm) MIP offered a two-fold superior binding affinity of the NHMAm only MIP, with KD values of 0.72μM and 1.67μM, respectively. A unique AA-dT:NHMAm MIP bilayer was created in an attempt to increase the amount AA-dT incorporated into the film, and this obtained a respectable KD value of 7.03μM. All MIPs produced excellent selectivity for the target protein and when applied to a sensor platform (Surface Plasma Resonance), the limit of detection for the MIPs is in the nM range (3.87, 3.47, and 3.87nM, for the NHMAm MIP, AA-dT:NHMAm MIP, and AA-dT:NHMAm MIP bilayer, respectively). The introduction of the modified thymine-based nucleobase offers a promising strategy for improving the properties of a MIP, allowing these MIPs to potentially be a highly robust and selective material for molecular recognition.

Improved Dose Response of N-(hydroxymethyl)acrylamide Gel Dosimeter with Calcium Chloride for Radiotherapy.

The impact of calcium chloride (CaCl2) on the performance of N-(hydroxymethyl)acrylamide (NHMA) polymer gel dosimeter is studied in this article. The dosimeter was exposed to doses of up to 10 Gy with radiation beam-energy of 10 MV and dose-rates of 300 cGy/min. The relaxation rate (R2) parameter was utilized to explore the performance of irradiated NHMAGAT gels. The dose response in terms of R2 increased from 0.29 to 0.63 Gy−1·s−1 with increasing calcium chloride concentration from 0 to 1000 mM. The results show no substantial impact of dose-rates as well as radiation energies on NHMAGAT samples. For the steadiness of irradiated NHMAGAT dosimeters, it was found that there is no apparent variation in R2 (less than ±3%; standard deviation) up to 3 days. The overall uncertainty of the gel dosimeter with calcium chloride is 4.96% (double standard deviation, 95% confidence level).

Improving the mechanical performance of P(N‐hydroxymethyl acrylamide/acrylic acid/2‐acrylamido‐2‐methylpropanesulfonic acid) hydrogel via hydrophobic modified nanosilica

AbstractHydrogels with high mechanical strength are essential for its most industrial applications. In this work, the hydrophobic SiO2nanoparticles (M‐SiO2NPs) modified with octadecyltrimethoxysilane were used as physical crosslinker to toughen the mechanical properties of hydrogels. The solution of monomers containing M‐SiO2NPs, N‐hydroxymethyl acrylamide (NHAM), acrylic acid (AA), 2‐acrylamido‐2‐methylpropanesulfonic acid (AMPS), was polymerized to prepare a P(NHAM/AA/AMPS)‐based composite hydrogel without any chemical cross‐linker. The composition and microstructure of the hydrogel were carefully studied with Fourier transform infrared spectroscopy and scanning electron microscopy. The mechanical properties of the hydrogel were investigated through compressive and tensile tests. Dynamic swelling tests were carried out at different pH values (1.0–12.0) and salinity (2000–20,000 mg/L) to study the acid resistance, alkali resistance, and salt resistance of the hydrogel. The obtained results showed that the hydrogel exhibited excellent mechanical performance, which was attributed to the unique 3D network formed by the hydrogen bond between M‐SiO2NPs and polymer as well as the hydrophobic association effect between the hydrophobic chains of M‐SiO2NPs. Furthermore, the hydrophobic association effect was enhanced when contacting with salt, acid, and alkali solutions, thus endowing the hydrogel with intensified salt resistance and wider acid–base adaptability range.

Strong, tough, anti-freezing, non-drying and sensitive ionic sensor based on fully physical cross-linked double network hydrogel

Ionic conductive double network (DN) sensors have attracted increasing attention in wearable electronic devices. However, their low mechanical and sensing properties as well as poor moisture retention and freezing resistance restrict severely their applications. Herein, we synthesized a fully physical cross-linked poly (N-hydroxymethyl acrylamide)/agar/ethylene glycol (PHA/Agar/EG) ionic conductive DN hydrogel exhibiting high strength and toughness, fast self-recovery, good fatigue resistance and good self-healing. Agar could form a physical network via reversible sol-gel transition, and interact with physical cross-linked poly (N-hydroxymethyl acrylamide) and sodium chloride (NaCl) via hydrogen bonds and salting-out effect, respectively. Meanwhile, ethylene glycol and NaCl improved the mechanical properties, long-lasting moisture retention and anti-freezing ability. The PHA/Agar/EG gel-based flexible sensor possessed excellent long-lasting and fatigue resistant sensing properties, and could monitor various human activities stably and sensitively. Therefore, this work would provide a simple and promising strategy to fabricate flexible sensors with integrated high performances for smart wearable devices.

Evaluation of acrylamide-based molecularly imprinted polymer thin-sheets for specific protein capture—a myoglobin model

We evaluate a series of thin-sheet hydrogel molecularly imprinted polymers (MIPs), using a family of acrylamide-based monomers, selective for the target protein myoglobin (Mb). The simple production of the thin-sheet MIP offers an alternative biorecognition surface that is robust, stable and uniform, and has the potential to be adapted for biosensor applications. The MIP containing the functional monomer N-hydroxymethylacrylamide (NHMAm), produced optimal specific rebinding of the target protein (Mb) with 84.9% (± 0.7) rebinding and imprinting and selectivity factors of 1.41 and 1.55, respectively. The least optimal performing MIP contained the functional monomer N,N-dimethylacrylamide (DMAm) with 67.5% (± 0.7) rebinding and imprinting and selectivity factors of 1.11 and 1.32, respectively. Hydrogen bonding effects, within a protein-MIP complex, were investigated using computational methods and Fourier transform infrared (FTIR) spectroscopy. The quantum mechanical calculations predictions of a red shift of the monomer carbonyl peak is borne-out within FTIR spectra, with three of the MIPs, acrylamide, N-(hydroxymethyl) acrylamide, and N-(hydroxyethyl) acrylamide, showing peak downshifts of 4, 11, and 8 cm−1, respectively.

Improved performance of N-(Hydroxymethyl)acrylamide gel dosimeter using potassium chloride for radiotherapy

In this study, polymer-gel dosimeters containing N-(Hydroxymethyl) acrylamide (NHMA) with different concentrations of potassium chloride (KCl) were developed and introduced for use in radiotherapy. The gels were irradiated with a megavolt X-ray photon beam up to 10 Gy using a medical linear accelerator. The irradiated NHMA_KCl dosimeters were evaluated by nuclear magnetic resonance (NMR), in terms of relaxation rate (R2). The results show that the dose sensitivity of polymer gel was improved by 33% when KCl concentration was increased from 0 to 1.9 wt%. The decrease in R2 values with increasing scanning temperature was 1.6% per °C at 6 Gy. The dosimeter was found stable within a period of 2–120 h after irradiation and is independent of dose-rate in the range of 50–600 cGy/min and independent of photon beam energy between 6 and 15 MV within 7.5% overall uncertainty.

Freezing-tolerant and robust gelatin-based supramolecular conductive hydrogels with double-network structure for wearable sensors

It is significant to design stretchable conductive hydrogels with high integrated mechanical and excellent anti-freezing performances for broadening their application fields. Herein, a freezing-tolerant and robust poly(N-hydroxymethyl acrylamide)/gelatin/glycerol supramolecular conductive hydrogel with double networks is synthesized via an one-pot method, where poly(N-hydroxymethyl acrylamide) can self-cross-link, and also interact with gelatin. Glycerol endows the conductive hydrogel with anti-freezing property in mechanics and electricity, and can also interact with poly(N-hydroxymethyl acrylamide) and gelatin to further enhance mechanical properties. Under optimal conditions, the conductive hydrogel exhibits high strength, super extensibility, rapid self-recovery, excellent fatigue resistance and high ionic conductivity. It possesses temperature insensitivity of mechanical properties and weak dependence of electrical behaviors on temperature. Furthermore, it exhibits excellent anti-freezing resistance response to strain, and can as sensor detect human activities. Thus, this work provides a simple and promising strategy for designing stretchable conductive gels with integrated high performances aiming for wearable intelligent electronics.