Special Issue "Aerogels 2018"
A special issue of Gels (ISSN 2310-2861).
Deadline for manuscript submissions: 27 May 2018
Dr. Francoise Quignard
Institut Charles Gerhardt-Montpellier, Matériaux Avancés pour la Catalyse et la Santé, UMR5253 CNRS-ENSCM-UM2-UM1, 8 rue de l'Ecole Normale, 34296 Montpellier, France
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Interests: polysaccharides; aerogel; textural properties; self-assembly; chemical modification; catalysis; medical devices
As you know well, “aerogel” is a broad term used for a special class of ultra-light porous materials. An aerogel is formed when a gel retains the structure of the parent gel upon drying, thus resulting in a highly porous material. These amazing materials provide advantages in terms of surface area, diffusion properties, thermal conductivity, refractive index, and dielectric constant. Thus, aerogels of inorganic or organic/bio-organic gels can find applications in a variety of domains, from super insulation and supercapacitors to trapping of molecules and biological entities, adsorbent, catalysts, sensors, and biomedical devices.
This Special Issue will provide an international forum for researchers to discuss the most recent studies concerning the preparation, characterization and applications of such aerogels. Through this Special Issue, the present state and future will be discussed by a wide range of authors.
Dr. Francoise Quignard
Dr. Nathalie Tanchoux
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 papers will be 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 quarterly journal published by MDPI.
Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) is waived for well-prepared manuscripts submitted to this issue. 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.
- textural properties
- thermal conductivity
- biomedical scaffold
- drug release
The below list represents only planned manuscripts. Some of these manuscripts have not been received by the Editorial Office yet. Papers submitted to MDPI journals are subject to peer-review.
Title: Developing Aerogel Surfaces via Switchable-Hydrophilicity Tertiary Amidine Coating for Improved Oil Recovery
Authors: Osman Karatum 1, Stephen A. Steiner III 2 and Desiree L. Plata 1,3
1 Department of Civil and Environmental Engineering, Hudson Hall, Duke University, Durham, NC 27707, USA 2 Aerogel Technologies, LLC, Boston, MA 02127, USA
3 Department of Chemical and Environmental Engineering, Mason Laboratory, Yale University, New Haven, CT 06511, USA
Abstract: Blanket aerogels (i.e., Cabot™ Thermal Wrap® (TW) and Aspen™ Spaceloft® (SL)) with surfaces that have controllable wettability are promising advanced materials for oil recovery applications, where high oil uptake during deployment could be coupled with high oil release to enable reusability of recovered oil.The study presented here details the preparation of CO2-switchable blanket aerogel surfaces through the synthesis and application of switchable-hydrophilicity tertiary amidine (i.e., tributylpentanamidine (TBPA)) onto aerogel blanket surfaces using drop casting, dip coating, and physical vapor deposition (PVD) techniques. The structure of the synthesized TBPA verified with 1H NMR, 13C NMR, and mass spectroscopy was and the deposition of TBPA was confirmed by X-ray photoelectron spectroscopy (XPS). Water contact angles on modified aerogel blanket surfaces in air and under a CO2 and water vapor were determined to identify hydrophobic-hydrophilic switchability. Our experiments revealed that surface coating of TBPA onto aerogel blankets was partially successful within limited set of process conditions (e.g., 290 ppm CO2 and 5500 ppm humidity for PVD, 106 ppm CO2 and 700 ppm humidity for drop casting and dip coating), but that the post-aerogel curing modification strategies yielded poor, heterogeneous reproducibility. Overall, more than 40 samples were tested for their switchability from hydrophobic to hydrophilic in the presence of CO2 and water vapor, respectively, and the success rate was 6.25, 11.7 and 18% for PVD, drop casting, and dip coating, respectively. The most likely reasons for unsuccessful coating onto aerogel surfaces are: (1) the heterogeneous fiber structure of the aerogel blankets, which is comprised of not only pure silica aerogel particles but also a mixture of polyester and/or fiberglass and (2) poor distribution of the chemical modifier TBPA over the aerogel blanket surface (i.e., poor coverage). Nevertheless, when successful, the aerogel hydrophobic-hydrophilic switchability produced the desired chemical behavior that should enhance oil recovery. These results indicate that pre-curing aerogel modification strategies, rather than post-curing depositional strategies, would improve the distribution and attachment of TBPA to the aerogel surfaces and enhance the performance of advanced aerogels for oil recovery operations.
Title: Prevention of aggregation of nanoparticles during the synthesis of nanogold-containing silica aerogels
Authors: István Lázár* and Hanna J. Szabó
Affiliations: Department of Inorganic and Analytical Chemistry, University of Debrecen, Egyetem tér 1, Debrecen, Hungary, H-4032, e-mail: firstname.lastname@example.org
Abstract: Nanogold is widely used in many areas of physics and chemistry due to its environment-sensitive plasmon resonance absorption. Immobilization of gold nanoparticles in highly porous silica aerogel offers an attractive alternative over liquid gold solutions as they show a mechanically stable structure, are permeable to gases and can be used even at elevated temperatures. We have found that the commercially available, citrate-stabilized 10 nm gold nanoparticles may suffer aggregation prior to or under the base-catalyzed gelation process of tetramethoxy silane. In the wet gels, Au particles showed increased sizes, changed shapes and loss of plasmon resonance absorption, due to the formation of larger aggregates. We have studied a range of water-miscible organic solvents, stabilizing agents and the gelation conditions to minimize changes occurring in the aerogel setting and supercritical drying process. It has been found that atmospheric carbon dioxide has a significant effect on aggregation, and it cannot be entirely excluded under normal synthetic conditions. Methanol resulted in an increase in the particle size only, dimethyl sulfoxide, dimethyl formamide, and urea changed the shape of nanoparticles converting to rod-like shapes, while diols led to an increase in both size and shape. However, using the polymeric stabilizer poly(vinyl pyrrolidone) efficiently prevented aggregation of the particles even in the presence of high concentration of carbon dioxide and allowed production of nanoAu containing silica aerogels in a single step, without modification of the technology.