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Koch SM, Dreimol CH, Goldhahn C, Maillard A, Stadler A, Künniger T, Grönquist P, Ritter M, Keplinger T, Burgert I. Biodegradable and Flexible Wood-Gelatin Composites for Soft Actuating Systems. ACS SUSTAINABLE CHEMISTRY & ENGINEERING 2024; 12:8662-8670. [PMID: 38872957 PMCID: PMC11167639 DOI: 10.1021/acssuschemeng.4c00306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Revised: 05/14/2024] [Accepted: 05/15/2024] [Indexed: 06/15/2024]
Abstract
Compliant materials are indispensable for many emerging soft robotics applications. Hence, concerns regarding sustainability and end-of-life options for these materials are growing, given that they are predominantly petroleum-based and non-recyclable. Despite efforts to explore alternative bio-derived soft materials like gelatin, they frequently fall short in delivering the mechanical performance required for soft actuating systems. To address this issue, we reinforced a compliant and transparent gelatin-glycerol matrix with structure-retained delignified wood, resulting in a flexible and entirely biobased composite (DW-flex). This DW-flex composite exhibits highly anisotropic mechanical behavior, possessing higher strength and stiffness in the fiber direction and high deformability perpendicular to it. Implementing a distinct anisotropy in otherwise isotropic soft materials unlocks new possibilities for more complex movement patterns. To demonstrate the capability and potential of DW-flex, we built and modeled a fin ray-inspired gripper finger, which deforms based on a twist-bending-coupled motion that is tailorable by adjusting the fiber direction. Moreover, we designed a demonstrator for a proof-of-concept suitable for gripping a soft object with a complex shape, i.e., a strawberry. We show that this composite is entirely biodegradable in soil, enabling more sustainable approaches for soft actuators in robotics applications.
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Affiliation(s)
- Sophie Marie Koch
- Wood
Materials Science, Institute for Building Materials, ETH Zurich, 8093 Zurich, Switzerland
- WoodTec
Group, Cellulose & Wood Materials, Empa, 8600 Duebendorf, Switzerland
| | - Christopher Hubert Dreimol
- Wood
Materials Science, Institute for Building Materials, ETH Zurich, 8093 Zurich, Switzerland
- WoodTec
Group, Cellulose & Wood Materials, Empa, 8600 Duebendorf, Switzerland
| | - Christian Goldhahn
- Wood
Materials Science, Institute for Building Materials, ETH Zurich, 8093 Zurich, Switzerland
| | - Aline Maillard
- Wood
Materials Science, Institute for Building Materials, ETH Zurich, 8093 Zurich, Switzerland
| | - Andrina Stadler
- Wood
Materials Science, Institute for Building Materials, ETH Zurich, 8093 Zurich, Switzerland
| | - Tina Künniger
- WoodTec
Group, Cellulose & Wood Materials, Empa, 8600 Duebendorf, Switzerland
| | - Philippe Grönquist
- University
of Stuttgart, Institute of Construction
Materials, Pfaffenwaldring 4, 70569 Stuttgart, Germany
- University
of Stuttgart, Materials Testing Institute, Pfaffenwaldring 4b, 70569 Stuttgart, Germany
| | - Maximilian Ritter
- Wood
Materials Science, Institute for Building Materials, ETH Zurich, 8093 Zurich, Switzerland
- WoodTec
Group, Cellulose & Wood Materials, Empa, 8600 Duebendorf, Switzerland
| | - Tobias Keplinger
- Wood
Materials Science, Institute for Building Materials, ETH Zurich, 8093 Zurich, Switzerland
| | - Ingo Burgert
- Wood
Materials Science, Institute for Building Materials, ETH Zurich, 8093 Zurich, Switzerland
- WoodTec
Group, Cellulose & Wood Materials, Empa, 8600 Duebendorf, Switzerland
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Koch SM, Goldhahn C, Müller FJ, Yan W, Pilz-Allen C, Bidan CM, Ciabattoni B, Stricker L, Fratzl P, Keplinger T, Burgert I. Anisotropic wood-hydrogel composites: Extending mechanical properties of wood towards soft materials' applications. Mater Today Bio 2023; 22:100772. [PMID: 37674781 PMCID: PMC10477686 DOI: 10.1016/j.mtbio.2023.100772] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Revised: 07/28/2023] [Accepted: 08/15/2023] [Indexed: 09/08/2023] Open
Abstract
Delignified wood (DW) offers a versatile platform for the manufacturing of composites, with material properties ranging from stiff to soft and flexible by preserving the preferential fiber directionality of natural wood through a structure-retaining production process. This study presents a facile method for fabricating anisotropic and mechanically tunable DW-hydrogel composites. These composites were produced by infiltrating delignified spruce wood with an aqueous gelatin solution followed by chemical crosslinking. The mechanical properties could be modulated across a broad strength and stiffness range (1.2-18.3 MPa and 170-1455 MPa, respectively) by varying the crosslinking time. The diffusion-led crosslinking further allowed to manufacture mechanically graded structures. The resulting uniaxial, tubular structure of the anisotropic DW-hydrogel composite enabled the alignment of murine fibroblasts in vitro, which could be utilized in future studies on potential applications in tissue engineering.
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Affiliation(s)
- Sophie Marie Koch
- Wood Materials Science, Institute for Building Materials, ETH Zurich, 8093 Zurich, Switzerland
- WoodTec Group, Cellulose & Wood Materials, Empa, 8600 Duebendorf, Switzerland
| | - Christian Goldhahn
- Wood Materials Science, Institute for Building Materials, ETH Zurich, 8093 Zurich, Switzerland
| | - Florence J. Müller
- Soft Materials Group, Department of Materials, ETH Zurich, 8093 Zurich, Switzerland
| | - Wenqing Yan
- Wood Materials Science, Institute for Building Materials, ETH Zurich, 8093 Zurich, Switzerland
- WoodTec Group, Cellulose & Wood Materials, Empa, 8600 Duebendorf, Switzerland
| | - Christine Pilz-Allen
- Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, 14476 Potsdam, Germany
| | - Cécile M. Bidan
- Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, 14476 Potsdam, Germany
| | - Beatrice Ciabattoni
- Wood Materials Science, Institute for Building Materials, ETH Zurich, 8093 Zurich, Switzerland
| | - Laura Stricker
- Wood Materials Science, Institute for Building Materials, ETH Zurich, 8093 Zurich, Switzerland
| | - Peter Fratzl
- Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, 14476 Potsdam, Germany
| | - Tobias Keplinger
- Wood Materials Science, Institute for Building Materials, ETH Zurich, 8093 Zurich, Switzerland
| | - Ingo Burgert
- Wood Materials Science, Institute for Building Materials, ETH Zurich, 8093 Zurich, Switzerland
- WoodTec Group, Cellulose & Wood Materials, Empa, 8600 Duebendorf, Switzerland
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Wang S, Li L, Zha L, Koskela S, Berglund LA, Zhou Q. Wood xerogel for fabrication of high-performance transparent wood. Nat Commun 2023; 14:2827. [PMID: 37198187 DOI: 10.1038/s41467-023-38481-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2022] [Accepted: 05/04/2023] [Indexed: 05/19/2023] Open
Abstract
Optically transparent wood has been fabricated by structure-retaining delignification of wood and subsequent infiltration of thermo- or photocurable polymer resins but still limited by the intrinsic low mesopore volume of the delignified wood. Here we report a facile approach to fabricate strong transparent wood composites using the wood xerogel which allows solvent-free infiltration of resin monomers into the wood cell wall under ambient conditions. The wood xerogel with high specific surface area (260 m2 g-1) and high mesopore volume (0.37 cm3 g-1) is prepared by evaporative drying of delignified wood comprising fibrillated cell walls at ambient pressure. The mesoporous wood xerogel is compressible in the transverse direction and provides precise control of the microstructure, wood volume fraction, and mechanical properties for the transparent wood composites without compromising the optical transmittance. Transparent wood composites of large size and high wood volume fraction (50%) are successfully prepared, demonstrating potential scalability of the method.
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Affiliation(s)
- Shennan Wang
- Division of Glycoscience, Department of Chemistry, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, AlbaNova University Centre, Stockholm, SE-106 91, Sweden
| | - Lengwan Li
- Wallenberg Wood Science Center, Department of Fibre and Polymer Technology, KTH Royal Institute of Technology, Stockholm, SE-100 44, Sweden
| | - Li Zha
- Division of Glycoscience, Department of Chemistry, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, AlbaNova University Centre, Stockholm, SE-106 91, Sweden
| | - Salla Koskela
- Division of Glycoscience, Department of Chemistry, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, AlbaNova University Centre, Stockholm, SE-106 91, Sweden
- Wallenberg Wood Science Center, Department of Fibre and Polymer Technology, KTH Royal Institute of Technology, Stockholm, SE-100 44, Sweden
| | - Lars A Berglund
- Wallenberg Wood Science Center, Department of Fibre and Polymer Technology, KTH Royal Institute of Technology, Stockholm, SE-100 44, Sweden
| | - Qi Zhou
- Division of Glycoscience, Department of Chemistry, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, AlbaNova University Centre, Stockholm, SE-106 91, Sweden.
- Wallenberg Wood Science Center, Department of Fibre and Polymer Technology, KTH Royal Institute of Technology, Stockholm, SE-100 44, Sweden.
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