Formation Of Composite Hydrogels Research Articles

Eco-Friendly g-C3N4/Carboxymethyl Cellulose/Alginate Composite Hydrogels for Simultaneous Photocatalytic Degradation of Organic Dye Pollutants.

The presented study was focused on the simple, eco-friendly synthesis of composite hydrogels of crosslinked carboxymethyl cellulose (CMC)/alginate (SA) with encapsulated g-C3N4 nanoparticles. The structural, textural, morphological, optical, and mechanical properties were determined using different methods. The encapsulation of g-C3N4 into CMC/SA copolymer resulted in the formation of composite hydrogels with a coherent structure, enhanced porosity, excellent photostability, and good adhesion. The ability of composite hydrogels to eliminate structurally different dyes with the same or opposite charge properties (cationic Methylene Blue and anionic Orange G and Remazol Brilliant Blue R) in both single- and binary-dye systems was examined through adsorption and photocatalytic reactions. The interactions between the dyes and g-C3N4 and the negatively charged CMC/SA copolymers had a notable influence on both the adsorption capacity and photodegradation efficiency of the prepared composites. Scavenger studies and leaching tests were conducted to gain insights into the primary reactive species and to assess the stability and long-term performance of the g-C3N4/CMC/SA beads. The commendable photocatalytic activity and excellent recyclability, coupled with the elimination of costly catalyst separation requirements, render the g-C3N4/CMC/SA composite hydrogels cost-effective and environmentally friendly materials, and strongly support their selection for tackling environmental pollution issues.

Ultrasound-triggered transglutaminase-catalyzed egg white-bovine gelatin composite hydrogel: Physicochemical and rheological studies

The present paper investigated gel properties and secondary structures of egg white-bovine gelatin composite hydrogels with different mass ratios upon ultrasound and transglutaminase pretreatment. The free sulfhydryl content increased with increasing gelatin in proteins mass ratio; however, longer probe sonication had an opposite effect on free sulfhydryl content and hydrogel solubility. The hydrogel solubility data revealed that proteins ratio and the pretreatment conditions (ultrasound duration and transglutaminase concentration) determined the contribution of non-covalent bonds (including electrostatic bonds, hydrogen bonds, and hydrophobic interactions) and covalent bonds (i.e., SS bridges) in the formation of composite hydrogels. Moreover, the hardness and storage modulus of hydrogels were improved with increasing gelatin in proteins mass ratio and ultrasound duration. Based on Fourier transform infrared spectroscopy and rheological data, helical structures had a great portion in composite hydrogels. Finally, the microstructure investigations showed that hydrogels formed the most porous structures at 50E:50G and 40E:60G (E: egg, G: gelatin) mass ratios.

Synthesis of nitrogen-doped reduced graphene oxide/SnO2 composite hydrogels and characterization of electrode materials

The macroscopic nitrogen-doped reduced graphene oxide/SnO2 composite hydrogels were synthesized by one-step hydrothermal method using graphene oxide and SnCl2 as precursors and ammonia water as nitrogen source. The graphene oxides were reduced to graphene during the hydrothermal process at the same time SnCl2 was oxidized to SnO2 nanoparticles that were uniformly anchored onto the graphene sheets, resulting in the assembly of nitrogen-doped reduced graphene oxide/SnO2 composite hydrogels. The feed ratio of graphene oxide to SnCl2 played a key role in the formation of composite hydrogel. The unique structure and the synergistic effect between nitrogen-doped reduced graphene oxide and SnO2 in the composite architectures not only provided the large surface area but also facilitated the transportation of ion and electron through the three-dimensional network. Therefore, the nitrogen-doped reduced graphene oxide/SnO2 composite hydrogel exhibited an improved capacity and high cycling stability, suggesting the composite hydrogels could be promising candidates for energy storage.

Synthesis and characterization of a novel pH-controllable composite hydrogel for anticancer drug delivery

A novel pH-sensitive composite hydrogel (CH) namely 2-Acrylamido-2-methylpropane sulfonic acid (AMPS) grafted N-maleoylchitosan (MACTS) intercalated montmorillonite has been synthesized by in situ intercalation graft copolymerization of AMPS with MACTS intercalated MMT (MACTS/MMT) by using potassium persulfate (KPS) as a free radical initiator, in the presence of N,N-methylenebisacrylamide (MBA) as a crosslinking agent. A hydrophilic anticancer drug, 5-fluorouracil (5-FLU), has been chosen to investigate the loading and release properties of the CH. The CH formation and 5-FLU loading ability of CH have been confirmed by FTIR. X-Ray diffraction (XRD) analysis supports the intercalation reaction of MACTS with MMT, since after intercalation reaction there is an increase in basal spacing. A scanning electron microscopy (SEM) image of drug loaded CH shows a smoother surface whereas blank CH has a cracked and rough surface, this reveals the high affinity of 5-FLU to CH. The encapsulation efficiency of CH reaches the maximum value of 94.0% with CH prepared using 4.0 g of MACTS/MMT, 1.5 g of AMPS, 0.75 g of MBA and 75.0% of drug loading. Swelling profiles obtained show that the CH swelling rate increases with increase of pH up to 6.4 and then starts to decrease. Release profiles of 5-FLU from CH have been studied under both simulated gastric and intestinal pH conditions. The results obtained show that the release rate of the loaded drug molecules was slow at pH 2.4 but increased significantly at pH 7.4. The cell viability test displayed that the 5-FLU loaded CH exhibited an enhanced cell inhibition than that of pure 5-FLU. The studies described in the paper demonstrate the potential viability of a pH-sensitive CH carrier for colon specific anticancer drugs.

Composite polymer hydrogels

Methods of preparing and properties of composite hydrogels based on various hydrophilic polymers and their mixtures with inorganic nanosized additives are considered. The effect of the type of physical or covalent bonding between components on the formation of composite hydrogels and their characteristics is discussed. The biphasic character of composite hydrogels determines as a rule their advantages as supersorbents, membrane materials, living-tissue substitutes, drug carriers, and soft-contact-lens materials.