DFG- Establishing International Collaboration

Development of biomimetic monolithic aerogel composite photocatalysts based on natural precursors for hydrogen generation by water splitting

Project Reference: MA 8575/5-1

Title: Chemically and structurally directed shape morphosis in hybrid aerogels for bone tissue engineering - Toward designing smart biomimetic 3D scaffold for bone cancer therapy and bone repair

Project Reference: MA 8575/3-1

Start: 10. 2021

Project 4: Ultra-light, reversible and anisotropically comprassible Nacre mimetic foam with assembly of biopolymer with 2D nanostructures

Silk fibroin (SF) is a multifunctional naturally occurring biopolymer that presented various illustrious properties like biocompatibility, biodegradability, and versatile processability. Recent SF aerogel so-called AeroSF, developed by Maleki et al.

With synergistic combination of surface chemistry modification, self-assembly, together with versatile directional freeze casting of combination of SF with 2D nanostructures of GO and MXene building blocks, Dr. Maleki, and her group have developed highly porous, ultralight and ultra-flexible monoliths with nacre- mimicking structure.

Project 1:  Cuttlefish Bone Mimetic Hybrid Aerogels with Hierarchical and Aligned Porosity, 

H. Maleki * et al.,  Biomacromolecules 2021, 22, 4, 1739–1751

Due to the current energy crises, the search for thermal energy management systems based on thermal insulating porous materials has drawn a significant deal of attention. Herein, we demonstrated the thermal insulation and management capabilities of cuttlefish bone mimetic aerogels with hierarchically organized porous structures directly fabricated from surface modified and self-assembled silk fibroin biopolymer extracted from b. Mori silkworm cocoon biomass hereafter, the materials developed referred to as X-AeroSF. Exploiting from creating an interpenetrating network of the secondary ceramic components of various one, two, and three-dimensional sepiolite (Mg2H2Si3O9.xH2O), MXene (Ti3C2TX) and silica nanostructures inside the self-assembled silk fibroin biopolymer and subsequent uni-directional freeze-casting and drying the resulted hydrogels, composites with aerogel feature were obtained. The obtained aerogels possess low bulk density (pb = 0.059-0.090 g cm-3), low thermal conductivities (0.035-0.042 W m-1 K-1), and high thermal stability (up to ~ 260 °C) with multi-modal lamella-bridge porous microstructures found in the cuttlefish bone structure. In addition, the intriguing anisotropy in the X-AeroSF composites porous structure enables thermal dissipation along with the aligned pore directions, thus decreasing the local overheating on the heated side. As a result, an improvement in thermal insulation in the perpendicular direction with respect to the pore lamellae was obtained. Therefore, the exquisite thermal energy management, biodegradability, low bulk density, fire resistivity, together with possible manufacture scalability of X-AeroSF composite, make this material attractive for future practical applications

Project 3: Hierarchical Assembly of Surface Modified Silk Fibroin Biomass into Micro‐, and Milli‐Metric Hybrid Aerogels with Core‐Shell, Janus, and Composite Configurations for Rapid Removal of Water Pollutants 

Bruder, V., Ludwig, T., Opitz, S., Christoffels, R., Fischer, T., Maleki, H.,* Adv. Mater. Interfaces 2021, 8, 2001892. https://doi.org/10.1002/admi.202001892

Multifunctional aerogels, with intriguing micro‐morphologies and macroscopic sizes, are fabricated for the first time from silk fibroin (SF) biopolymer extracted from Bombyx mori silkworm cocoon to optimize the adsorption performances of heavy metal ions and soluble organic pollutants. By a synergistic combination of approaches such as surface‐modification of SF with polyethyleneimine (PEI) and its hierarchical cryo‐assembly with graphene oxide into various macrostructures, namely core‐shell, composite, and Janus, series of millimetric aerogels (2–3 mm) with interesting center divergent honeycomb micro‐morphologies are prepared. In addition, cryo‐assembly assisted electro‐spraying of SF‐PEI led to obtaining micro‐aerogels (74 µm), possessing a wrinkled surface morphology with a high surface area. The aerogel beads exhibit superior adsorption capacities for Cu²⁺ (186.7 mg g⁻¹, in 240 min) with a regeneration potential, but also for anionic dyes, for example, methylene orange (811.3 mg g⁻¹) and organic solvents (1138 g g⁻¹% for chloroform). The large adsorption capacities and fast adsorption kinetics of cations obtained by these aerogels are attributed to their impressive micro‐morphologies and small geometries, enabling rapid diffusion and cations uptake. Therefore, the sustainability, biodegradability, ease of fabrications, rapid, and reusable adsorption performance make aerogel beads of this study highly potent for multipollutant adsorption.