Multifunctional Polymer Nano-, Micro- and Hydro- Gels: Synthesis, Properties and Applications

A special issue of Gels (ISSN 2310-2861). This special issue belongs to the section "Gel Applications".

Deadline for manuscript submissions: closed (30 September 2024) | Viewed by 13727

Special Issue Editors


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Guest Editor
School of Biomedical Engineering, Guangdong Medical University, Dongguan 523808, China
Interests: polymers and colloids; nanogels; biomaterials; fluorescent nanoprobe; hydrogels and adhesives

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Guest Editor
College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
Interests: microgels and nanogels; colloidosomes; microcapsules; hydrogels; surface and interface chemistry; supermolecules; soft device

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Guest Editor
School of Materials and Chemical Engineering, Zhengzhoug University of Light Industry, Zhengzhou 450001, China
Interests: microgels; hydrogels; smart polymers

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Guest Editor
School of Mechanical Engineering, Northwestern Polytechanical University, Xi’an 710072, China
Interests: bioprinting; bioscaffold; biomaterials; polymeric hydrogels; molecular simulation
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Special Issue Information

Dear Colleagues,

This Special Issue on “Multifunctional Polymer Nano-, Micro- and Hydro- Gels: Synthesis, Properties and Applications” is dedicated to the recent advances in the macro- and micro-hydrogel field. Within this context, a broad range of subjects, including hydrogel preparation and characterization, mechanism expression, and applications, will be discussed.

Hydrogels are 3D cross-linked polymer networks with a high content of water, which can be divided into macroscopic and microscopic gels according to their size. Macroscopic gels are usually directly referred to as hydrogels because of their large size and can be discerned by the naked eye. Microscopic gels are also called microgels or nanogels; scholars generally consider hydrogels with a size of 20-200 nm to be nanogels, and those with a size larger than 200 nm to be microgels. In recent years, macro- and micro-hydrogels have been widely developed and applied in biomedical engineering, antibacterial coatings, soft robots, flexible materials and other fields due to their advantages of softness, swellability, a fast response and good biocompatibility.

This Special Issue focuses on the design of functional macro- and micro-hydrogels by controlling their synthesis and characterization, including theoretical and fundamental aspects. Their physical and chemical properties can be affected by factors such as the choice of monomers, polymers and crosslinking methods. Research should cover new methods and ideas for preparing gels, and the construction of new functional hydrogel materials which have advanced interdisciplinary applications.

We look forward to receiving your valued contribution to this Special Issue.

Dr. Mingning Zhu
Dr. Wenkai Wang
Dr. Ruixue Liu
Dr. Qinghua Wei
Guest Editors

Manuscript Submission Information

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Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Gels is an international peer-reviewed open access monthly journal published by MDPI.

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Keywords

  • multifunctional gels
  • multiscale structure
  • stimuli responses
  • multiple sensing
  • colloids and interfaces
  • mechanical character
  • biomaterials
  • flexible electronics
  • controlled release
  • photoluminescence probe
  • adhesives and dressings

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Published Papers (9 papers)

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Research

20 pages, 5034 KiB  
Article
Development and Characterization of a Sol–Gel-Functionalized Glass Carbon Electrode Probe for Sensing Ultra-Trace Amounts of NH3 and NH4+ in Water
by H. Alwael, M. Oubaha and M. S. El-Shahawi
Gels 2024, 10(6), 382; https://doi.org/10.3390/gels10060382 - 4 Jun 2024
Viewed by 889
Abstract
This study centers on the development and characterization of an innovative electrochemical sensing probe composed of a sensing mesoporous functional sol–gel coating integrated onto a glassy carbon electrode (sol–gel/GCE) for the detection of NH3 and/or NH4+ in water. The main [...] Read more.
This study centers on the development and characterization of an innovative electrochemical sensing probe composed of a sensing mesoporous functional sol–gel coating integrated onto a glassy carbon electrode (sol–gel/GCE) for the detection of NH3 and/or NH4+ in water. The main interest for integrating a functional sol–gel coating onto a GCE is to increase the selective and sensing properties of the GCE probe towards NH3 and/or NH4+ ions. The structure and surface morphology of the newly developed sol–gel/GCE probe were characterized employing scanning electron microscopy (SEM), atomic force microscopy (AFM), dynamic light scattering (DLS), and Fourier-transform infrared (FTIR), while the electrochemical sensing properties were evaluated by Berthelot’s reaction, cyclic voltammetry (CV), and adsorptive square wave–anodic striping voltammetry (Ads SW–ASV). It is shown that the newly developed sol–gel coating is homogeneously deposited on the GCE with a sub-micron and uniform thickness close to 630 nm and a surface roughness of 25 nm. The sensing testing of the sol–gel/GCE probe showed limits of detection and limits of quantitation of 1.7 and 5.56 nM of NH4+, respectively, as well as a probe sensitivity of 5.74 × 10−1 μA/μM cm−2. The developed probe was fruitfully validated for the selective detection of NH3/NH4+ in fresh and sea water samples. Computed Student texp (0.45–1.25) and Fexp (1.69–1.78) (n = 5) tests were less than the theoretical ttab (2.78) and Ftab (6.39) at 95% probability. Full article
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16 pages, 566 KiB  
Article
Usefulness of Capillary Gel Electrophoresis-Based PCR for Detection of Clostridioides difficile Strains with Hypervirulent Ribotypes
by Tomasz Bogiel, Alicja Dura, Marcin Woźniak, Agnieszka Mikucka and Piotr Kanarek
Gels 2024, 10(5), 343; https://doi.org/10.3390/gels10050343 - 17 May 2024
Viewed by 1293
Abstract
Clostridioides difficile is a complex of anaerobic bacteria responsible for the epidemics of post-antibiotic diarrhea as one of the examples of CDI (Clostridioides difficile infection). As many as 70% of cases concern hospitalized patients, particularly those in intensive care units. Ribotyping is [...] Read more.
Clostridioides difficile is a complex of anaerobic bacteria responsible for the epidemics of post-antibiotic diarrhea as one of the examples of CDI (Clostridioides difficile infection). As many as 70% of cases concern hospitalized patients, particularly those in intensive care units. Ribotyping is one of the most common methods for differentiating bacterial strains. The purpose of this work was to show the effectiveness of the gel electrophoresis-based PCR ribotyping method and the Webribo database for typing C. difficile isolates, including the hypervirulent 027 ribotype. DNA samples extracted from 69 C. difficile strains with previously marked genotypes were included in this study. PCR was performed using 16S–23S primers, and capillary gel electrophoresis was performed on the Applied Biosystem 3130xl Genetic Analyzer. The Webribo database was applied for ribotype assignment. Out of 69 samples, 48 belonged to already known ribotypes, 13 represented new ribotypes and 8 was indicated as similar to the existing ones, having some differences. Capillary gel electrophoresis-based PCR is an effective method for the differentiation of C. difficile ribotypes and can be recognized as a very useful tool in epidemiological studies, while the Webribo database is a useful and an accessible database for a quick analysis of C. difficile ribotypes. Full article
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15 pages, 7536 KiB  
Article
Preparation and Performance Evaluation of Temperature-Resistant and Salt-Resistant Gels
by Xudong Li, Meilong Fu and Jiani Hu
Gels 2024, 10(5), 337; https://doi.org/10.3390/gels10050337 - 16 May 2024
Cited by 2 | Viewed by 1075
Abstract
In order to improve the plugging performance of high-temperature and high-salt oil reservoir plugging agents, this paper utilizes a copolymer composed of acrylamide and 2-acrylamide-2-methylpropanesulfonic acid (AM/AMPS) as the polymer, polyethyleneimine as the cross-linking agent, and nylon fiber as the stabilizer to develop [...] Read more.
In order to improve the plugging performance of high-temperature and high-salt oil reservoir plugging agents, this paper utilizes a copolymer composed of acrylamide and 2-acrylamide-2-methylpropanesulfonic acid (AM/AMPS) as the polymer, polyethyleneimine as the cross-linking agent, and nylon fiber as the stabilizer to develop a high-temperature- and high-salt-resistant gel system. This study analyzed and evaluated the temperature resistance, salt resistance and blocking performance of the gel system. The evaluation results show that the gel-forming strength of this gel system can reach an H level, and it has good thermal stability at the high temperature of 130 °C. At the high salinity of 240,720 mg/L, the syneresis rate remains below 2.5%, and the gel-forming time is greater than 15 h; the higher the temperature, the shorter the gelling time. The results of our sand-filled pipe-plugging experiment show that the gel system can adapt to sand-filled pipes with different levels of permeability, and reaching a plugging rate of 94%. Full article
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18 pages, 11763 KiB  
Article
Investigations on the Impact of a Series of Alkoxysilane Precursors on the Structure, Morphology and Wettability of an Established Zirconium-Modified Hybrid Anticorrosion Sol–Gel Coating
by H. Alwael, E. MacHugh, M. S. El-Shahawi and M. Oubaha
Gels 2024, 10(5), 315; https://doi.org/10.3390/gels10050315 - 5 May 2024
Viewed by 1255
Abstract
The current study reports on the impact of a series of functional alkoxysilanes on the wettability and structure of a well-established silicon/zirconium hybrid anticorrosion sol–gel coating. The selected functional alkoxysilanes comprise tetra ethylorthosilicate (TEOS), 3-glycidyloxypropyltrimethoxysilane (GPTMS), 3-aminopropyltriethoxysilane (APTES) and vinyltriethoxysilane (VTES) and are [...] Read more.
The current study reports on the impact of a series of functional alkoxysilanes on the wettability and structure of a well-established silicon/zirconium hybrid anticorrosion sol–gel coating. The selected functional alkoxysilanes comprise tetra ethylorthosilicate (TEOS), 3-glycidyloxypropyltrimethoxysilane (GPTMS), 3-aminopropyltriethoxysilane (APTES) and vinyltriethoxysilane (VTES) and are incorporated at various concentrations (1, 5, 10 and 20%) within the silicon/zirconium sol–gel material. The prepared materials are successfully processed as coatings and cured at different temperatures in the range of 100–150 °C. The characterisation of the structures and surfaces is performed by dynamic light scattering (DLS), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), silicon nuclear magnetic resonance spectroscopy (29Si-NMR), atomic force microscopy (AFM) and static water contact angle (WCA). Structural characterisations (DLS, FTIR,29Si-NMR) show that the functional alkoxysilanes effectively bind at the surface of the reference sol–gel material, resulting in the formation of functional core–shell nanoparticles. WCA results show that the hydrophobic properties of all materials decrease with curing temperature, and AFM analysis demonstrated that this behaviour is associated with a decrease in roughness. The physico-chemical processes taking place are critically assigned and discussed. Full article
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13 pages, 3180 KiB  
Article
A High-Stretching, Rapid-Self-Healing, and Printable Composite Hydrogel Based on Poly(Vinyl Alcohol), Nanocellulose, and Sodium Alginate
by Mingyang Li, Yanen Wang, Qinghua Wei, Juan Zhang, Xiaohu Chen and Yalong An
Gels 2024, 10(4), 258; https://doi.org/10.3390/gels10040258 - 11 Apr 2024
Viewed by 1690
Abstract
Hydrogels with excellent flexibility, conductivity, and controllable mechanical properties are the current research hotspots in the field of biomaterial sensors. However, it is difficult for hydrogel sensors to regain their original function after being damaged, which limits their practical applications. Herein, a composite [...] Read more.
Hydrogels with excellent flexibility, conductivity, and controllable mechanical properties are the current research hotspots in the field of biomaterial sensors. However, it is difficult for hydrogel sensors to regain their original function after being damaged, which limits their practical applications. Herein, a composite hydrogel (named SPBC) of poly(vinyl alcohol) (PVA)/sodium alginate (SA)/cellulose nanofibers (CNFs)/sodium borate tetrahydrate was synthesized, which has good self-healing, electrical conductivity, and excellent mechanical properties. The SPBC0.3 hydrogel demonstrates rapid self-healing (<30 s) and achieves mechanical properties of 33.92 kPa. Additionally, it exhibits high tensile strain performance (4000%). The abundant internal ions and functional groups of SPBC hydrogels provide support for the good electrical conductivity (0.62 S/cm) and electrical response properties. In addition, the SPBC hydrogel can be attached to surfaces such as fingers and wrists to monitor human movements in real time, and its good rheological property supports three-dimensional (3D) printing molding methods. In summary, this study successfully prepared a self-healing, conductive, printable, and mechanically superior SPBC hydrogel. Its suitability for 3D-printing personalized fabrication and outstanding sensor properties makes it a useful reference for hydrogels in wearable devices and human motion monitoring. Full article
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15 pages, 4499 KiB  
Article
A Lignin Silver Nanoparticles/Polyvinyl Alcohol/Sodium Alginate Hybrid Hydrogel with Potent Mechanical Properties and Antibacterial Activity
by Jie Yu, Fangli Ran, Chenyu Li, Zhenxin Hao, Haodong He, Lin Dai, Jingfeng Wang and Wenjuan Yang
Gels 2024, 10(4), 240; https://doi.org/10.3390/gels10040240 - 1 Apr 2024
Cited by 1 | Viewed by 2161
Abstract
Antibacterial hydrogels have attracted significant attention due to their diverse applications, efficient antimicrobial properties, and adaptability to various environments and requirements. However, their relatively fragile structure, coupled with the potential for environmental toxicity when exposed to their surroundings for extended periods, may significantly [...] Read more.
Antibacterial hydrogels have attracted significant attention due to their diverse applications, efficient antimicrobial properties, and adaptability to various environments and requirements. However, their relatively fragile structure, coupled with the potential for environmental toxicity when exposed to their surroundings for extended periods, may significantly limit their practical application potential. In this work, a composite hydrogel was synthesized with outstanding mechanical features and antibacterial capability. The hydrogel was developed through the combination of the eco-friendly and enduring antibacterial agent, lignin silver nanoparticles (Lig-Ag NPs), with polyvinyl alcohol (PVA) and sodium alginate (SA), in varying proportions. The successful synthesis of the hydrogel and the dispersed distribution of Lig-Ag NPs within the hydrogel were confirmed by various analytical techniques, including field emission scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), mercury intrusion porosimetry (MIP), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The formation of multiple hydrogen bonds between Lig-Ag NPs and the composites contributed to a more stable and dense network structure of the hydrogel, consequently enhancing its mechanical properties. Rheological tests revealed that the hydrogel exhibited an elastic response and demonstrated outstanding self-recovery properties. Significantly, the antibacterial hydrogel demonstrated effectiveness against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), achieving a <5% survival of bacteria within 12 h. This study presented a green and straightforward synthetic strategy for the application of antibacterial composite hydrogels in various fields. Full article
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16 pages, 5585 KiB  
Article
Stretchable Magneto-Mechanical Configurations with High Magnetic Sensitivity Based on “Gel-Type” Soft Rubber for Intelligent Applications
by Vineet Kumar and Sang-Shin Park
Gels 2024, 10(1), 80; https://doi.org/10.3390/gels10010080 - 21 Jan 2024
Cited by 1 | Viewed by 1293
Abstract
“Gel-type” soft and stretchable magneto-mechanical composites made of silicone rubber and iron particles are in focus because of their high magnetic sensitivity, and intelligence perspective. The “intelligence” mentioned here is related to the “smartness” of these magneto-rheological elastomers (MREs) to tune the “mechanical [...] Read more.
“Gel-type” soft and stretchable magneto-mechanical composites made of silicone rubber and iron particles are in focus because of their high magnetic sensitivity, and intelligence perspective. The “intelligence” mentioned here is related to the “smartness” of these magneto-rheological elastomers (MREs) to tune the “mechanical stiffness” and “output voltage” in energy-harvesting applications by switching magnetic fields. Hence, this work develops “gel-type” soft composites based on rubber reinforced with iron particles in a hybrid with piezoelectric fillers such as barium titanate. A further aspect of the work relies on studying the mechanical stability of intelligence and the stretchability of the composites. For example, the stretchability was 105% (control), and higher for 158% (60 per 100 parts of rubber (phr) of barium titanate, BaTiO3), 149% (60 phr of electrolyte iron particles, EIP), and 148% (60 phr of BaTiO3 + EIP hybrid). Then, the magneto-mechanical aspect will be investigated to explore the magnetic sensitivity of these “gel-type” soft composites with a change in mechanical stiffness under a magnetic field. For example, the anisotropic effect was 14.3% (60 phr of EIP), and 4.4% (60 phr of hybrid). Finally, energy harvesting was performed. For example, the isotropic samples exhibit ~20 mV (60 phr of BaTiO3), ~5.4 mV (60 phr of EIP), and ~3.7 mV (60 phr of hybrid). However, the anisotropic samples exhibit ~5.6 mV (60 phr of EIP), and ~8.8 mV (60 phr of hybrid). In the end, the composites prepared have three configurations, namely one with electro-mechanical aspects, another with magnetic sensitivity, and a third with both features. Overall, the experimental outcomes will make fabricated composites useful for different intelligent and stretchable applications. Full article
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13 pages, 9634 KiB  
Article
Ion Partition in Polyelectrolyte Gels and Nanogels
by Alexandros Chremos, Matan Mussel, Jack F. Douglas and Ferenc Horkay
Gels 2023, 9(11), 881; https://doi.org/10.3390/gels9110881 - 7 Nov 2023
Viewed by 1331
Abstract
Polyelectrolyte gels provide a load-bearing structural framework for many macroscopic biological tissues, along with the organelles within the cells composing tissues and the extracellular matrices linking the cells at a larger length scale than the cells. In addition, they also provide a medium [...] Read more.
Polyelectrolyte gels provide a load-bearing structural framework for many macroscopic biological tissues, along with the organelles within the cells composing tissues and the extracellular matrices linking the cells at a larger length scale than the cells. In addition, they also provide a medium for the selective transportation and sequestration of ions and molecules necessary for life. Motivated by these diverse problems, we focus on modeling ion partitioning in polyelectrolyte gels immersed in a solution with a single type of ionic valence, i.e., monovalent or divalent salts. Specifically, we investigate the distribution of ions inside the gel structure and compare it with the bulk, i.e., away from the gel structure. In this first exploratory study, we neglect solvation effects in our gel by modeling the gels without an explicit solvent description, with the understanding that such an approach may be inadequate for describing ion partitioning in real polyelectrolyte gels. We see that this type of model is nonetheless a natural reference point for considering gels with solvation. Based on our idealized polymer network model without explicit solvent, we find that the ion partition coefficients scale with the salt concentration, and the ion partition coefficient for divalent ions is higher than for monovalent ions over a wide range of Bjerrum length (lB) values. For gels having both monovalent and divalent salts, we find that divalent ions exhibit higher ion partition coefficients than monovalent salt for low divalent salt concentrations and low lB. However, we also find evidence that the neglect of an explicit solvent, and thus solvation, provides an inadequate description when compared to experimental observations. Thus, in future work, we must consider both ion and polymer solvation to obtain a more realistic description of ion partitioning in polyelectrolyte gels. Full article
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19 pages, 9456 KiB  
Article
From Poly(glycerol itaconate) Gels to Novel Nonwoven Materials for Biomedical Applications
by Magdalena Miętus, Krzysztof Kolankowski, Tomasz Gołofit, Piotr Denis, Aleksandra Bandzerewicz, Maciej Spychalski, Marcin Mąkosa-Szczygieł, Maciej Pilarek, Kamil Wierzchowski and Agnieszka Gadomska-Gajadhur
Gels 2023, 9(10), 788; https://doi.org/10.3390/gels9100788 - 29 Sep 2023
Viewed by 1797
Abstract
Electrospinning is a process that has attracted significant interest in recent years. It provides the opportunity to produce nanofibers that mimic the extracellular matrix. As a result, it is possible to use the nonwovens as scaffolds characterized by high cellular adhesion. This work [...] Read more.
Electrospinning is a process that has attracted significant interest in recent years. It provides the opportunity to produce nanofibers that mimic the extracellular matrix. As a result, it is possible to use the nonwovens as scaffolds characterized by high cellular adhesion. This work focused on the synthesis of poly(glycerol itaconate) (PGItc) and preparation of nonwovens based on PGItc gels and polylactide. PGItc gels were synthesized by a reaction between itaconic anhydride and glycerol. The use of a mixture of PGItc and PLA allowed us to obtain a material with different properties than with stand-alone polymers. In this study, we present the influence of the chosen ratios of polymers and the OH/COOH ratio in the synthesized PGItc on the properties of the obtained materials. The addition of PGItc results in hydrophilization of the nonwovens’ surface without disrupting the high porosity of the fibrous structure. Spectral and thermal analyzes are presented, along with SEM imagining. The preliminary cytotoxicity research showed that nonwovens were non-cytotoxic materials. It also helped to pre-determine the potential application of PGItc + PLA nonwovens as subcutaneous tissue fillers or drug delivery systems. Full article
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