Smart strain sensing organic–inorganic hybrid hydrogels with nano barium ferrite as the cross-linker

2019 ◽  
Vol 7 (8) ◽  
pp. 2353-2360 ◽  
Author(s):  
Hongbo Gu ◽  
Hongyuan Zhang ◽  
Chao Ma ◽  
Hongling Sun ◽  
Chuntai Liu ◽  
...  
Keyword(s):  
Polyacrylic Acid ◽  
Barium Ferrite ◽  
Hysteresis Loops ◽  
Strain Sensing ◽  
Hybrid Hydrogel ◽  
Inorganic Hybrid ◽  
Hybrid Hydrogels ◽  
Cross Linker ◽  
The Cross ◽  
Sensing Performance

Polyacrylic acid hybrid hydrogel with nano barium ferrite as a cross-linker exhibits stable piezoresistive sensing performance with negligible hysteresis loops.

scholarly journals Mineral plastic hydrogels from the cross-linking of polyacrylic acid and alkaline earth or transition metal ions

2019 ◽  
Vol 55 (34) ◽  
pp. 4913-4916 ◽  
Author(s):  
David J. Schupp ◽  
Xiaotong Zhang ◽  
Shengtong Sun ◽  
Helmut Cölfen
Keyword(s):  
Transition Metal ◽  
Metal Ions ◽  
Polyacrylic Acid ◽  
Alkaline Earth ◽  
Transition Metal Ions ◽  
Cross Linking ◽  
Inorganic Hybrid ◽  
Ph Values ◽  
Hybrid Hydrogels ◽  
The Cross

Based on ‘Mineral Plastics’, organic–inorganic hybrid hydrogels were synthesized by utilization of different metal ions and pH-values.

SWELLING DESWELLING STUDIES AFTER FREEZE–THAW TREATMENT OF NANOSILICA REINFORCED POLY (VINYL ALCOHOL)-BASED ORGANIC–INORGANIC HYBRID HYDROGEL

2011 ◽  
Vol 10 (04n05) ◽  
pp. 1087-1090
Author(s):  
TRIDIB BHUNIA ◽  
LUNA GOSWAMI ◽  
DIPANKAR CHATTOPADHYAY ◽  
ABHIJIT BANDYOPADHYAY
Keyword(s):  
Vinyl Alcohol ◽  
Room Temperature ◽  
Size Range ◽  
Poly Vinyl Alcohol ◽  
Particle Size Range ◽  
Hybrid Hydrogel ◽  
Inorganic Hybrid ◽  
Freeze Thaw ◽  
Hybrid Hydrogels ◽  
Different Molecular Weight

Aqueous nanosilica sol (particle size range: 9–13 nm, pH: 9.0) was added at various low concentration range (0.5–2 wt.%) into aqueous poly (vinyl alcohol) (PVA) of different molecular weight (98% hydrolyzed, 20 wt.%) (pH: 5.0) at room temperature under constant stirring to synthesize organic-inorganic hybrid hydrogels in presence of sodium lauryl sulphate as a silica dispersant. Buffer tablets were added to arrest the pH at 9.0 (to prevent any silica aggregation due to change in pH). The resultant hybrids were cast on Teflon sheets and dried in an oven at 50°C to drive out all the unbound water. Those films were then subjected to freese-thaw treatment continuously for 5 h. The freese-thawed films appeared opaque. The swelling-de swelling experiments with the hydrogels were carried out in distilled water at room temperature and consequently allowed to de-swell naturally. Those observations were correlated with the microstructures of the hybrid hydrogels.

Robust and rapid responsive organic-inorganic hybrid bilayer hydrogel actuators with silicon nanoparticles as the cross-linker

Polymer ◽  
2021 ◽  
pp. 123863
Author(s):  
Bing-Zi Yang ◽  
Shu-Ya Zhang ◽  
Ping-Hua Wang ◽  
Chun-Hua Liu ◽  
Yuan-Yuan Zhu
Keyword(s):  
Silicon Nanoparticles ◽  
Inorganic Hybrid ◽  
Cross Linker ◽  
The Cross

scholarly journals Superabsorbent poly(acrylic acid) and antioxidant poly(ester amide) hybrid hydrogel for enhanced wound healing

2021 ◽  
Vol 8 (2) ◽  
Author(s):  
Jianhua Zhang ◽  
Junfei Hu ◽  
Baoshu Chen ◽  
Tianbao Zhao ◽  
Zhipeng Gu
Keyword(s):  
Wound Healing ◽  
Acrylic Acid ◽  
Protein Denaturation ◽  
Healing Process ◽  
Antioxidant Properties ◽  
Skin Damage ◽  
Hybrid Hydrogel ◽  
Hydrogel Scaffolds ◽  
Hybrid Hydrogels ◽  
Poly Acrylic Acid

Abstract Wound healing dressing is increasingly needed in clinical owing to the large quantity of skin damage annually. Excessive reactive oxygen species (ROS) produced through internal or external environmental influences can lead to lipid peroxidation, protein denaturation, and even DNA damage, and ultimately have harmful effects on cells. Aiming to sufficiently contact with the wound microenvironment and scavenge ROS, superabsorbent poly (acrylic acid) and antioxidant poly (ester amide) (PAA/PEA) hybrid hydrogel has been developed to enhance wound healing. The physical and chemical properties of hybrid hydrogels were studied by Fourier-transform infrared (FTIR) absorption spectrum, compression, swelling, degradation, etc. Besides, the antioxidant properties of hybrid hydrogels can be investigated through the free radical scavenging experiment, and corresponding antioxidant indicators have been tested at the cellular level. Hybrid hydrogel scaffolds supported the proliferation of human umbilical vein endothelial cells and fibroblasts, as well as accelerated angiogenesis and skin regeneration in wounds. The healing properties of wounds in vivo were further assessed on mouse skin wounds. Results showed that PAA/PEA hybrid hydrogel scaffolds significantly accelerated the wound healing process through enhancing granulation formation and re-epithelialization. In summary, these superabsorbent and antioxidative hybrid hydrogels could be served as an excellent wound dressing for full-thickness wound healing.

scholarly journals Effect of the Cross-Linking Density on the Swelling and Rheological Behavior of Ester-Bridged β-Cyclodextrin Nanosponges

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 478
Author(s):  
Gjylije Hoti ◽  
Fabrizio Caldera ◽  
Claudio Cecone ◽  
Alberto Rubin Pedrazzo ◽  
Anastasia Anceschi ◽  
...  
Keyword(s):  
Scale Up ◽  
Future Application ◽  
Cross Linking ◽  
Synthesis Reaction ◽  
Dependent Behavior ◽  
Cyclodextrin Nanosponges ◽  
Potential Applications ◽  
Cross Linker ◽  
The Cross ◽  
Shed Light

The cross-linking density influences the physicochemical properties of cyclodextrin-based nanosponges (CD-NSs). Although the effect of the cross-linker type and content on the NSs performance has been investigated, a detailed study of the cross-linking density has never been performed. In this contribution, nine ester-bridged NSs based on β-cyclodextrin (β-CD) and different quantities of pyromellitic dianhydride (PMDA), used as a cross-linking agent in stoichiometric proportions of 2, 3, 4, 5, 6, 7, 8, 9, and 10 moles of PMDA for each mole of CD, were synthesized and characterized in terms of swelling and rheological properties. The results, from the swelling experiments, exploiting Flory–Rehner theory, and rheology, strongly showed a cross-linker content-dependent behavior. The study of cross-linking density allowed to shed light on the efficiency of the synthesis reaction methods. Overall, our study demonstrates that by varying the amount of cross-linking agent, the cross-linked structure of the NSs matrix can be controlled effectively. As PMDA βCD-NSs have emerged over the years as a highly versatile class of materials with potential applications in various fields, this study represents the first step towards a full understanding of the correlation between their structure and properties, which is a key requirement to effectively tune their synthesis reaction in view of any specific future application or industrial scale-up.

Self-assembled three-dimensional hierarchical graphene hybrid hydrogels with ultrathin β-MnO2 nanobelts for high performance supercapacitors

2015 ◽  
Vol 3 (4) ◽  
pp. 1540-1548 ◽  
Author(s):  
Sheng Zhu ◽  
Hui Zhang ◽  
Ping Chen ◽  
Lin-Hui Nie ◽  
Chuan-Hao Li ◽  
...  
Keyword(s):  
Self Assembly ◽  
High Performance ◽  
Three Dimensional ◽  
The Self ◽  
Mass Loading ◽  
Hybrid Hydrogel ◽  
Precise Control ◽  
Ultrafine Structure ◽  
Hybrid Hydrogels ◽  
Self Assembled

A facile protocol for the self-assembly of the rGO/β-MnO2 hybrid hydrogel with ultrafine structure and precise control of mass-loading for high performance supercapacitors is reported.

scholarly journals Synthesis, Characterization of a New Polyacrylic Acid Superabsorbent, Some Heavy Metal Ion Sorption, the Adsorption Isotherms, and Quantum Chemical Investigation

Materials ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4390
Author(s):  
Sevil Savaskan Yilmaz ◽  
Nuri Yildirim ◽  
Murat Misir ◽  
Yasin Misirlioglu ◽  
Emre Celik
Keyword(s):  
Heavy Metal ◽  
Quantum Chemical ◽  
Metal Ion ◽  
Molecular Mechanic ◽  
Ion Concentration ◽  
Heavy Metal Ion ◽  
Competitive Sorption ◽  
Cross Linker ◽  
The Cross

Poly(acrylic acid/Kryptofix 23-Dimethacrylate) superabsorbent polymer [P (AA/Kry23-DM) SAP] was synthesized by solution polymerization to remove Co, Ni, Cu, Cd, Mn, Zn, Pb, Cr, and Fe ions in water and improve the quality of the water. Kry23-DM cross-linker (1,4,7,13,16-Pentaoxa-10,19 diazo cyclohexene icosane di methacrylate) was synthesized using Kry23 and methacryloyl chloride. The characterization of the molecules was done by FTIR, TGA, DSC, and SEM techniques. The effects of parameters such as pH, concentration, and the metal ion interaction on the heavy metal ions uptaking of SAP was investigated. It was observed that P (AA/Kry23-DM) SAP has maximum water absorption, and the absorption increases with the pH increase. Adsorption rates and sorption capacity, desorption ratios, competitive sorption (qcs), and distribution coefficient (log D) of P(AA/Kry23-DM) SAP were studied as a function of time and pH with the heavy metal ion concentration. Langmuir and Freundlich isotherms of the P (AA/Kry23-DM) SAP were investigated to verify the metal uptake. Molecular mechanic (MM2), Assisted Model Building with Energy Refinement (AMBER), and optimized potentials for liquid simulations (OPLS) methods. were used in quantum chemical calculations for the conformational analysis of the cross-linker and the SAP. ΔH0f calculations of the cross-linker and the superabsorbent were made using Austin Model 1(AM1) method.

scholarly journals ADSORBATIVE SEPARATION OF DOXYCYCLINE FROM AQUEOUS SOLUTION WITH N,N-DIETHYL N-METHYL CHITOSAN, GUM AND POLYACRYLIC ACID BASED HYDROGELS

2021 ◽  
Vol 11 (07) ◽  
pp. 44-53
Author(s):  
Mirvari Hasanova Mirvari Hasanova
Keyword(s):  
Aqueous Solution ◽  
Ion Exchange ◽  
Zeta Potential ◽  
Polyacrylic Acid ◽  
Inorganic Materials ◽  
Biologically Active ◽  
Cross Linking ◽  
Separation And Purification ◽  
Inorganic Substances ◽  
The Cross

The separation and purification of antibiotics with sorption by ion-exchange materials, as well as their delivery in biological processes by immobilization, are now widely used in biotechnology. There are many scientific studies in the literature on the sorption of antibiotics by polymer-based sorbents and inorganic materials, as well as the study of thermodynamics and kinetics of the process. In the literature, the acquisition of biologically active systems from the sorption of antibiotics by ion-exchange fibers based on various polymers and inorganic substances was carried out. However, the synthesis of selective gels for the effective separation of doxycycline and its delivery in different pH mediums by sorption with biodegradable, biocompatible polysaccharide-containing composites is one of the topical issues. Gel was synthesized from the cross-linking of N,N-diethyl N-methyl derivative of a natural polyaminosaccharide of chitosan by glutaric aldehyde. Also, pH-sensitive hydrogels that can swollen in water were synthesized from the cross-linking of a graft copolymer of cherry source gummiarabic with N-vinylpyrrolidone, as well as synthetic polymer polyacrylic acid with N,N-methylene-bis-acrylamide. The structure of the gels were identified by FTIR and NMR spectroscopy, and the sorption of doxycycline antibiotic from an aqueous solution was investigated. According to the values of zeta potential, the protonation of functional groups in the main macromolecule in an acidic medium leads to a value of zeta potential of 40÷80 mV on the surface of chitosan-based gel and others. Although the chemical structure is different, the isoelectric point is set around pH=6÷8 for all three hydrogels. The dependences of the sorption process on the amount of gels, antibiotic concentration, temperature, and pH medium were studied. The experimental data were analyzed using two adsorption models, Langmuir and Freundlich, with the later system providing the best fit. Doxycycline is adsorbed on the surface of chitosan, gummiarabic and polyacrylic acid based hydrogel composite through by physical interactions. Also, the results of thermodynamic parameters ΔG40 kJ/mol show that the nature of the adsorption process is physical, and spontaneous, too. Keywords: Chitosan, Gummiarabic-arabinogalactane, polyacrylic acid, hydrogel, sorption isoterms, doxycycline, thermodynamica.

scholarly journals Cross-linker system between neurofilaments, microtubules and membranous organelles in frog axons revealed by the quick-freeze, deep-etching method

1982 ◽  
Vol 94 (1) ◽  
pp. 129-142 ◽  
Author(s):  
N Hirokawa
Keyword(s):  
Chemical Extraction ◽  
Distilled Water ◽  
Deep Etching ◽  
Cross Links ◽  
Cross Linker ◽  
The Cross ◽  
Cross Bridges ◽  
20 Nm ◽  
Soluble Material ◽  
Soluble Components

The elaborate cross-connections among membranous organelles (MO), microtubules (MT), and neurofilaments (NF) were demonstrated in unifixed axons by the quick-freeze, deep-etch, and rotary-shadowing method. They were categorized into three groups: NF-associated cross-linker, MT-associated cross-bridges, and long cross-links in the subaxolemmal space. Other methods were also employed to make sure that the observed cross-connections in the unfixed axons were not a result of artifactual condensation or precipitation of soluble components or salt during deep-etching. Axolemma were permeablized either chemically (0.1% saponin) or physically (gentle homogenization), to allow egress of their soluble components from the axon; or else the axons were washed with distilled water after fixation. After physical rupture of the axolemma or saponin treatment, most of the MO remained intact. MT were stabilized by adding taxol in the incubation medium. Axons prepared by these methods contained many longitudinally oriented NF connected to each other by numerous fine cross-linkers (4-6 nm in diameter, 20-50 nm in length). Two specialized regions were apparent within the axons: one composed of fascicles of MT linked with each other by fine cross-bridges; the other was in the subaxolemmal space and consisted of actinlike filaments and a network of long cross-links (50-150 nm) which connected axolemma and actinlike filaments with NF and MT. F-actin was localized to the subaxolemmal space by the nitrobenzooxadiazol phallacidin method. MO were located mainly in these two specialized regions and were intimately associated with MT via fine short (10-20 nm in length) cross-bridges. Cross-links from NF to MO and MT were also common. All these cross-connections were observed after chemical extraction or physical rupture of the axon; however, these procedures removed granular materials which were attached to the filaments in the fresh unextracted axons. The cross-connections were also found in the axons washed with distilled water after fixation. I conclude that the cross- connections are real structures while the granular material is composed of soluble material, probably protein in nature.

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