scholarly journals pH-Sensitive Hydrogel from Polyethylene Oxide and Acrylic acid by Gamma Radiation

2019 ◽  
Vol 3 (2) ◽  
pp. 58 ◽  
Author(s):  
Tania Sabnam Binta Monir ◽  
Sadia Afroz ◽  
Ruhul A. Khan ◽  
Muhammed Yusuf Miah ◽  
Makoto Takafuji ◽  
...  
Keyword(s):  
Acrylic Acid ◽  
Gamma Radiation ◽  
Polyethylene Oxide ◽  
Chloride Salt ◽  
Swelling Ratio ◽  
Ph Responsive ◽  
Salt Solutions ◽  
Sem Images ◽  
Gel Content ◽  
Scanning Electron

Hydrogel as a good water absorbent has attracted great research interest. A series of hydrogel based on polyethylene oxide (PEO) and acrylic acid (AAc) was prepared by applying gamma radiation with variation in the concentration of acrylic acid. Fourier transform infrared (FTIR) and scanning electron microscopy (SEM) were used to characterize the PEO/ AAc hydrogel. The properties of the prepared hydrogels such as gel content, swelling behavior, tensile strength, and pH sensitivity were evaluated. The formation of the hydrogels was confirmed from FTIR spectra. SEM images showed the inner porous structure of the hydrogels. The dose of gamma radiation was optimized to get a hydrogel with good swelling property and mechanical strength. The swelling ratio and gel content of the hydrogels were increased with increasing acrylic acid content. The pH of the solutions affected the swelling which indicated the pH-responsive property of the prepared hydrogels. Swelling of the prepared hydrogels in sodium chloride salt solutions decreased with increasing the ionic strength.

scholarly journals Synthesis and Characterization Superabsorbent Hydrogels of Partially Neutralized Acrylic Acid Prepared Using Gamma Irradiation; Swelling and Thermal Behavior

2015 ◽  
Vol 15 (3) ◽  
pp. 281-287 ◽  
Author(s):  
Erizal Erizal ◽  
Basril Abbas ◽  
Sulistioso Giat Sukaryo ◽  
Dhena Ria Barleany
Keyword(s):  
Acrylic Acid ◽  
Gamma Radiation ◽  
Thermal Behavior ◽  
Synthesis And Characterization ◽  
Swelling Ratio ◽  
Optimum Conditions ◽  
Dsc Studies ◽  
Large Numbers ◽  
End Products ◽  
Superabsorbent Hydrogels

A series of superabsorbent hydrogels were synthesized from partially neutralized acrylic acid with varying degree of neutralization (0-1) using gamma radiation. The effects of degree neutralization of acrylic acid on swelling ratio were studied. DSC measurement was performed to understand the type of end products resulting from irradiation. The morphologies of the hydrogels were examined using SEM. The chemical changes of the hydrogels were characterized using FTIR. At optimum conditions (10 kGy, 15 min), the hydrogels with neutralization degree 0.5 exhibited rapid swelling with the highest swelling ratio ~1000 g/g. The results of DSC studies confirmed the possible formation of the type hydrogels from irradiated partially neutralized acrylic acid, and the hydrogels showed large numbers of pores from SEM examination.

scholarly journals Fabrication, Structure and Functional Characterizations of pH-Responsive Hydrogels Derived from Phytoglycogen

Foods ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 2653
Author(s):  
Xiuting Hu ◽  
Yao Liu ◽  
Yimei Chen ◽  
Tao Zhang ◽  
Ming Miao
Keyword(s):  
Electrostatic Repulsion ◽  
Swelling Ratio ◽  
Ph Responsive ◽  
X Ray Diffraction ◽  
Carrier System ◽  
Bioactive Substances ◽  
X Ray ◽  
Gelation Rate ◽  
Responsive Hydrogels ◽  
Scanning Electron

The pH-responsive hydrogels were obtained through successive carboxymethylation and phosphorylase elongatation of phytoglycogen and their structure and functional characterizations were investigated. Phytoglycogen (PG) was first carboxymethylated to obtain carboxymethyl phytoglycogen (CM-PG) with degree of substitution (DS) at 0.15, 0.25, 0.30, and 0.40, respectively. Iodine staining and X-ray diffraction analysis suggested that the linear glucan chains were successfully phosphorylase-elongated from the non-reducing ends at the CM-PG surface and assembled into the double helical segments, leading to formation of the hydrogel. The DS of CM-PG significantly influenced elongation of glucan chains. Specifically, fewer glucan chains were elongated for CM-PG with higher DS and the final glucan chains were shorter, resulting in lower gelation rate of chain-elongated CM-PG and lower firmness of the corresponding hydrogels. Scanning electron microscope observed that the hydrogels exhibited a porous and interconnected morphology. The swelling ratio and volume of hydrogels was low at pH 3–5 and then became larger at pH 6–8 due to electrostatic repulsion resulting from deprotonated carboxymethyl groups. Particularly, the hydrogel prepared from chain-elongated CM-PG (DS = 0.25) showed the highest sensitivity to pH. These results suggested that phosphorylase-treated CM-PG formed the pH-responsive hydrogel and that the elongation degree and the properties of hydrogels depended on the carboxymethylation degree. Thus, it was inferred that these hydrogels was a potential carrier system of bioactive substances for their targeted releasing in small intestine.

scholarly journals Microscopy Methods for Biofilm Imaging: Focus on SEM and VP-SEM Pros and Cons

Biology ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 51
Author(s):  
Michela Relucenti ◽  
Giuseppe Familiari ◽  
Orlando Donfrancesco ◽  
Maurizio Taurino ◽  
Xiaobo Li ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Ion Beam ◽  
Ruthenium Red ◽  
Variable Pressure ◽  
Sem Images ◽  
Advantages And Disadvantages ◽  
Pros And Cons ◽  
Microscopy Techniques ◽  
Scanning Electron

Several imaging methodologies have been used in biofilm studies, contributing to deepening the knowledge on their structure. This review illustrates the most widely used microscopy techniques in biofilm investigations, focusing on traditional and innovative scanning electron microscopy techniques such as scanning electron microscopy (SEM), variable pressure SEM (VP-SEM), environmental SEM (ESEM), and the more recent ambiental SEM (ASEM), ending with the cutting edge Cryo-SEM and focused ion beam SEM (FIB SEM), highlighting the pros and cons of several methods with particular emphasis on conventional SEM and VP-SEM. As each technique has its own advantages and disadvantages, the choice of the most appropriate method must be done carefully, based on the specific aim of the study. The evaluation of the drug effects on biofilm requires imaging methods that show the most detailed ultrastructural features of the biofilm. In this kind of research, the use of scanning electron microscopy with customized protocols such as osmium tetroxide (OsO4), ruthenium red (RR), tannic acid (TA) staining, and ionic liquid (IL) treatment is unrivalled for its image quality, magnification, resolution, minimal sample loss, and actual sample structure preservation. The combined use of innovative SEM protocols and 3-D image analysis software will allow for quantitative data from SEM images to be extracted; in this way, data from images of samples that have undergone different antibiofilm treatments can be compared.

Triply-responsive OEG-based microgels and hydrogels: Regulation of swelling ratio, volume phase transition temperatures and mechanical properties

2021 ◽  
Author(s):  
Dongdong Lu ◽  
Mingning Zhu ◽  
Jing Jin ◽  
Brian R. Saunders
Keyword(s):  
Phase Transition ◽  
Biomedical Engineering ◽  
Volume Phase Transition ◽  
Swelling Ratio ◽  
Transition Temperatures ◽  
Ph Responsive ◽  
Network Systems ◽  
Volume Phase ◽  
Phase Transition Temperatures ◽  
Volume Swelling

Thermally- and pH-responsive microgels (MGs) and hydrogels are fascinating network systems that have been applied in biomedical engineering and sensing. The volume-swelling ratio (Q) and the volume-phase transition temperatures (VPTTs)...

Characterization and measurement of gamma radiation shielding of a new tungsten-lignin composite

2021 ◽  
pp. 002199832110293
Author(s):  
Armando Cirilo de Souza ◽  
Flavio Aristone ◽  
Adriana Fatima Gomes Gouvea ◽  
Hedielly Brasil Fernandes ◽  
Adailto Miyai ◽  
...  
Keyword(s):  
Gamma Radiation ◽  
Kraft Lignin ◽  
Temperature Treatment ◽  
Radiation Shielding ◽  
X Rays ◽  
Clear Indication ◽  
Pure Tungsten ◽  
Metal Organic ◽  
Gamma Radiations ◽  
Scanning Electron

This research has been carried on to analyze the capability of a new composite to be effectively used as shielding of gamma radiation. The preparation of a metal-organic composite formed by tungsten and Kraft lignin is presented. Samples have been characterized through X-rays and scanning electron microscopy measurements. The results led to the study of the different phase formations. The microscopic analyzes indicate that two different phases are present in the composite. The absence of oxidation in the process even after the temperature treatment imposed to form the sample has also been noticed. Measurements of the attenuation have been performed to study its ability to absorb gamma radiation. A sample of cobalt 60 (Co-60), for which the peak energies are at 1173 keV and 1332 keV, was used as a source of gamma radiation in the experiment of attenuation. The measured attenuation of gamma radiations when the composite is placed to act as a shield is only 16% smaller than the attenuation obtained for standard pure tungsten. This is a clear indication that the new metal-organic composite is suitable for the fabrication of devices dedicated to shielding radiation, with the advantage of being easier to manipulate.

Dendritic magnetite decorated by pH-responsive PEGylated starch: a smart multifunctional nanocarrier for the triggered release of anti-cancer drugs

RSC Advances ◽  
2015 ◽  
Vol 5 (60) ◽  
pp. 48586-48595 ◽  
Author(s):  
Ali Pourjavadi ◽  
Zahra Mazaheri Tehrani ◽  
Seyed Hassan Hosseini
Keyword(s):  
Acrylic Acid ◽  
Cancer Drugs ◽  
Ph Responsive ◽  
Triggered Release ◽  
Anti Cancer ◽  
Poly Acrylic Acid

In the present study, we designed a pH-responsive drug nanocarrier based on polyamidoamine-modified Fe3O4 nanoparticles coated by PEGylated starch-co-poly(acrylic acid).

The Photoluminescence Enhancement and Stability of Porous Silicon by Cathodic Reduction and Acid Treatment

2014 ◽  
Vol 887-888 ◽  
pp. 458-461
Author(s):  
Chang Qing Li ◽  
Kun Wang ◽  
Pei Jia Liu ◽  
Qi Ming
Keyword(s):  
Electron Microscope ◽  
Porous Silicon ◽  
Acid Treatment ◽  
Cathodic Reduction ◽  
Luminescence Properties ◽  
Sem Images ◽  
Photoluminescence Enhancement ◽  
The Stability ◽  
Scanning Electron ◽  
Cathode Reduction

Porous silicon (PSi) was fabricated by using electrochemical anodic etching method. Then acid treatment and cathode reduction treatment were employed to improve the luminescence properties and stability of PSi material. Photoluminescence (PL) measurements and scanning electron microscope (SEM) were used to observe the luminescence properties and microstructure of samples, respectively. The results of PL measurements showed that the PL intensity and the stability of luminescence of samples after cathodic reduction and acid treatment were significantly improved. The SEM images showed that the porosity of PSi may be increased through the cathodic reduction treated.

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