Biopolymer‐Aerogele und ‐Schäume: Chemie, Eigenschaften und Anwendungen

Zhao, Shanyu; Malfait, Wim J.; Guerrero‐Alburquerque, Natalia; Koebel, Matthias M.; Nyström, Gustav

doi:10.1002/ange.201709014

Cited by 24 publications

(8 citation statements)

References 375 publications

(542 reference statements)

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“…Porous materials, such as aerogels, exhibit a power-law scaling relation between Young's modulus and the bulk density ( ) [38][39][40] . Such scaling behavior is also specifically observed in other polysaccharide-based aerogels [41][42][43][44][45] . Table 3 shows the effect of zein on the bulk densities of the aerogels, where a decreasing trend from Z0→Z1→Z2 and an increasing trend from Z2→Z3→Z4 were observed.…”

Section: Methodssupporting

confidence: 62%

Stability Studies of Starch Aerogel Formulations for Biomedical Applications

et al. 2020

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Starch aerogels are attractive materials for biomedical applications due to their low density and high open porosity coupled with high surface areas. However, the lack of macropores in conventionally-manufactured polysaccharide aerogels is a limitation to their use as scaffolds for regenerative medicine. Moreover, the stability under storage of polysaccharide aerogels is critical for biomedical purposes and scarcely studied so far. In this work, the induction of a new macropore population (1-2 µm) well-integrated in the starch aerogel backbone was successfully achieved by the incorporation of zein as a porogen. The obtained dual-porous aerogels were evaluated in terms of composition as well as morphological, textural and mechanical properties. Stability of aerogels upon storage mimicking the zone II (25 ºC, 65 % relative humidity) according to International Conference on Harmonization (ICH) guideline of climatic conditions was checked after 1 and 3 months from morphological, physicochemical and mechanical perspectives. Zein incorporation induced remarkable changes in the mechanical performance of the end aerogel products and showed a preventive effect on the morphological changes during the storage period.

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Section: Methodssupporting

confidence: 62%

Stability Studies of Starch Aerogel Formulations for Biomedical Applications

et al. 2020

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“…Dispersion of fibrous components derived from biomaterials, such as cellulose nanofibers from bacteria28 or plants,29,30 pectin,31 as well as chitosan,32,33 in which the fibre acts as a continuous template or scaffold within the network skeleton in order to mechanically support the delicate structure of silica aerogels, was also reported and nicely summarized in a very recent all-embracing review 34. Mixing of these bio-derived fibres with silica is typically performed via in situ sol–gel processing in the presence of an organosilane coupling agent or through soaking the pre-formed silica gel in the biopolymer solution.…”

Section: Introductionmentioning

confidence: 97%

“…Also, the mechanical strength and toughness of silk fibres are superior to the best synthetic materials such as Kevlar38 or common biopolymers such as collagen and poly- l -lactic acid (PLA). However, except for a very recent report of the groups of Mallepally et al ,39 who developed an SF-based aerogel through a CO 2 assisted gelation technique, and Omenetto et al ,40 who investigated biopolymer-based hierarchical constructs, the formation of SF aerogels by solution processes has not been reported 34…”

Section: Introductionmentioning

confidence: 99%

Novel multifunctional polymethylsilsesquioxane–silk fibroin aerogel hybrids for environmental and thermal insulation applications

2018

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“…In many cases, this requires more time along with the necessity for the extensive use of (non-green) organic solvents during the synthesis/polymerization and postsynthesis processing [2]. These shortcomings, however, have been solved by replacing these oil-based polymers with green biopolymers from various natural, renewable resources, such as different polysaccharide-based polymers, e.g., bacterial and plant-based cellulose [5]. One promising example in this regard is the work published by Cai et al [6] in which the in-situ incorporation/gelation of tetraalkoxysilanes inside a cellulose-based fiber network conferred a very good mechanical resiliency to the resulting hybrid gels.…”

Section: Introductionmentioning

confidence: 99%

Silica-silk fibroin hybrid (bio)aerogels: two-step versus one-step hybridization

Maleki

Huesing

2019

J Sol-Gel Sci Technol

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In this study, silk fibroin as a highly promising naturally occurring biopolymer extracted from silkworm cocoon is applied to mechanically reinforce silica aerogels. To this aim, two different approaches for the incorporation of silk fibroin into the silica network are compared: (1) a one-step acid catalyzed and (2) a two-step acid-base catalyzed sol-gel reaction. The total organosilane concentration, as well as the SF to silane mass fractions, regulated the hybridization process to proceed either through a one-step or two-step sol-gel reaction. In both processes, for an efficient chemical mixing the silk fibroin components with the silane phase, a silane coupling agent, 5-(trimethoxysilyl) pentanoic acid (TMSPA), comprising carboxylic acid groups and a pentyl hydrocarbon chain has been used. For a low organosilane content (3.4 mmol) along with a high SF to silane mass ratio (15-30%), the gelation of the silane and silk fibroin phases took place in a one-pot/one-step process in the presence of an acid catalyst in an entirely aqueous system. In the two-step synthesis approach, which was applied for high initial silane contents (17 mmol), and low SF to silane mass ratios (1-4%), first, the gelation of the silk fibroin phase was triggered by addition of an acid catalyst followed by a more pronounced condensation of the silane catalyzed by the addition of the base. Both synthesis approaches led to materials with promising mechanical propertiesbeing 1) the one-step process resulting in gels with much better compressibility (up to 70% of strain), low density (0.17-0.22 g cm −3 ) and three orders of magnitude improvement in the Young's modulus (13.5 MPa) compared to that of the pristine silica aerogel but with rather high shrinkage (30-40%). The two-step process in principle could result in the hybrid aerogel with interesting bulk density (0.17-0.28 g cm −3 ) with lower shrinkage (10%), but the resultant aerogel was stiff and fragile. Also, both approaches led to a significant reduction in the time required to prepare strong hybrid aerogels compared to conventional hybrid polymer-silica aerogels with the utilization of an entirely aqueous synthesis approach for a wide range of applications. ;,: 1234567890();,:Highlights • Silk fibroin (SF) biopolymer is an interesting biopolymer for mechanical reinforcement of silica aerogel.• Two sustainable sol-gel based approaches are proposed for hybridization of silica with SF. •Hybrids obtained by the one step sol-gel synthesis approach demonstrate better mechanical performance.• Molar ratio of SF to organosilanes is the most determinant factor for resulting final properties.• Both synthesis approaches led to significant reduction in the time required for preparation of strong hybrid aerogels.

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Biopolymer‐Aerogele und ‐Schäume: Chemie, Eigenschaften und Anwendungen

Cited by 24 publications

References 375 publications

Stability Studies of Starch Aerogel Formulations for Biomedical Applications

Stability Studies of Starch Aerogel Formulations for Biomedical Applications

Novel multifunctional polymethylsilsesquioxane–silk fibroin aerogel hybrids for environmental and thermal insulation applications

Silica-silk fibroin hybrid (bio)aerogels: two-step versus one-step hybridization

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