Advances in Synthetic and Bio-Based Aerogels: Mechanical Properties, Thermal Insulation, and Environmental Remediation (2nd Edition)

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

Deadline for manuscript submissions: 30 September 2025 | Viewed by 1859

Special Issue Editors


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Guest Editor
1. Department of Chemical Engineering, CERES, University of Coimbra, Rua Sílvio Lima, 3030-790 Coimbra, Portugal
2. Cellular Materials Laboratory (CellMat), Department of Condensed Material Physics, Facultad de Ciencias, University of Valladolid, 47011 Valladolid, Spain
Interests: aerogels; thermal insulation; foams; porous materials; biopolymers; polyurethane
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Special Issue Information

Dear Colleagues,

This Special Issue on “Advances in Synthetic and Bio-based Aerogels: Mechanical Properties, Thermal Insulation, and Environmental Remediation (2nd Edition)” is dedicated to recent innovative studies on the synthesis procedures and distinctive characteristics of aerogels for the referred applications.

The huge relevance of this topic in the development of advanced materials for our increasingly technological society promotes the high number of papers that are currently being published in scientific journals. Therefore, this Special Issue is gathering research describing the production of aerogels through different methods and an exhaustive characterization in terms of textural properties, chemical composition, thermal insulation, mechanical properties, and uncommon adsorptive/catalytic performance, among others.

Aerogels usually present a unique combination of properties that can be tuned through changes in the production process that significantly alter their nanostructures. There are several procedures for tailoring the final properties of these materials by modifying the formulations, inducing changes in structure through different processing steps, adding different fillers, etc.

Thus, papers describing structure–property relationships, heat transfer modelling, mechanical reinforcing techniques, and the adsorptive- or catalytic-enhancing modifications of aerogels are welcome. Moreover, the presented works may provide an approach to different applications in the fields of building, aerospace, energy management, medicine, and environmental remediation.

We encourage authors to contribute to this Special Issue, which aims to provide valuable knowledge for the aerogel community.

Dr. Beatriz Merillas
Dr. Luísa Durães
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

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.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2100 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • aerogels
  • thermal insulation
  • mechanical properties
  • porous structure
  • environmental remediation

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Related Special Issue

Published Papers (3 papers)

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Research

26 pages, 8645 KiB  
Article
Effect of the Gel Drying Method on Properties of Semicrystalline Aerogels Prepared with Different Network Morphologies
by Glenn A. Spiering, Garrett F. Godshall and Robert B. Moore
Gels 2025, 11(6), 447; https://doi.org/10.3390/gels11060447 - 10 Jun 2025
Abstract
The purpose of this study was to investigate the effect of different drying methods on the structure and properties of semicrystalline polymer aerogels. Aerogels, consisting of either globular or strut-like morphologies, were prepared from poly(ether ether ketone) (PEEK) or poly(phenylene sulfide) (PPS) and [...] Read more.
The purpose of this study was to investigate the effect of different drying methods on the structure and properties of semicrystalline polymer aerogels. Aerogels, consisting of either globular or strut-like morphologies, were prepared from poly(ether ether ketone) (PEEK) or poly(phenylene sulfide) (PPS) and dried using vacuum drying, freeze-drying, or supercritical CO2 extraction. Vacuum drying was found to result in aerogels with a higher shrinkage, smaller mesopores (with pore widths of 2–50 nm), and smaller surface areas compared to the use of supercritical extraction as the drying method. Freeze-dried aerogels tended to have properties between those of vacuum-dried aerogels and aerogels prepared with supercritical extraction. High network connectivity was found to lead to improved gel modulus, which increased the ability of aerogels to resist network deformation due to stresses induced during drying. The PEEK and PPS aerogel networks consisting of highly connected strut-like features were considerably stiffer than those composed of globular features, and thus shrank less under the forces induced by vacuum drying or freeze-drying. The aerogels prepared from PPS were found to have larger mesopores and smaller surface areas than the aerogels prepared from PEEK. The larger mesopores of the PPS aerogels induced lower capillary stresses on the aerogel network, and thus shrank less. This work demonstrates that preparing PEEK and PPS gels with strut-like features can allow aerogel processing with simpler evaporative drying methods rather than the more complex supercritical drying method. Full article
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15 pages, 4162 KiB  
Article
Alginate/k-Carrageenan Interpenetrated Biopolymeric Aerogels for Nutraceutical Drug Delivery
by Alessandra Zanotti, Lucia Baldino, Ernesto Reverchon and Stefano Cardea
Gels 2025, 11(6), 393; https://doi.org/10.3390/gels11060393 - 27 May 2025
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Abstract
Bioactive compounds of natural origin are central to the development of nutraceutical formulations. To improve their stability and to target their delivery to the intestinal or colonic tract, alginate/k-carrageenan spherical gels have been produced at different volumetric ratios (100/0, 70/30, 50/50, 30/70, and [...] Read more.
Bioactive compounds of natural origin are central to the development of nutraceutical formulations. To improve their stability and to target their delivery to the intestinal or colonic tract, alginate/k-carrageenan spherical gels have been produced at different volumetric ratios (100/0, 70/30, 50/50, 30/70, and 0/100 v/v), by means of solution dripping and external gelation. Different drying methods were compared, and only through supercritical technologies was it possible to achieve interpenetrated networks that feature nanometric pore size distribution. Hybrid aerogels inherited the most relevant characteristics of alginate and k-carrageenan: they showed remarkable water uptake capacity (e.g., 50.60 g/g), and stability in aqueous media over large timespans. Naringin release tests in simulated intestinal and colonic fluids proved that it is possible to target drug delivery by choosing intermediate alginate/k-carrageenan ratios. Overall, by means of supercritical gel drying, it is possible to generate advanced biopolymeric aerogels, yielding fully natural interpenetrated networks that valorize the most compelling properties of each species involved. Full article
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21 pages, 7145 KiB  
Article
Studying the Size-Dependence of Graphene Nanoplatelets (GNPs) in the Final Properties of Polyurethane Aerogels: Thermal Insulation and Mechanical Strength
by Jaime Lledó, Judith Martín-de León, Tomás E. Gómez Álvarez-Arenas, Miguel Ángel Rodríguez-Pérez and Beatriz Merillas
Gels 2025, 11(1), 44; https://doi.org/10.3390/gels11010044 - 7 Jan 2025
Viewed by 1351
Abstract
In the present work, the influence of the addition of graphene nanoplatelets presenting different dimensions on polyurethane–polyisocyanurate aerogel structure and properties has been studied. The obtained aerogels synthesized through a sol–gel method have been fully characterized in terms of density, porosity, specific surface [...] Read more.
In the present work, the influence of the addition of graphene nanoplatelets presenting different dimensions on polyurethane–polyisocyanurate aerogel structure and properties has been studied. The obtained aerogels synthesized through a sol–gel method have been fully characterized in terms of density, porosity, specific surface area, mechanical stiffness, thermal conductivity, and speed of sound. Opacified aerogels showing high porosity (>92%) and low densities (78–98 kg/m3) have been produced, and the effect of the size and content of graphene nanoplatelets has been studied. It has been observed that formulations with less than 5 wt.% of graphene nanoplatelets larger than 2 microns can effectively reduce the total thermal conductivity by absorption and scattering of the infrared radiation, reducing the heat transfer by this mechanism. The resulting opacified samples are highly insulating materials, with thermal conductivities less than 18 mW/m·K. Moreover, it has been observed that smaller particles with ca. 200 nm of average length can promote an increase in the elastic modulus, therefore obtaining stiffer aerogels, combined with thermal conductivities lower than 20 mW/m·K. Results have been studied in detail, providing a further understanding of the mechanisms for improving the final properties of these materials, making them more suitable for industrial applications. Full article
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