| 研究開始時の研究の概要 |
We envisage that, CNFs can be unidirectionally oriented using our established methods. A dispersion of oriented CNFs can be fixed via cross-linking the interfacial hydroxyl groups with divalent molecules, silica matrix or resorcinol-formaldehyde network. Thus obtained aerogels exhibit typically high porosity and excellent thermal insulating properties. In addition, strong interfacial interactions between cross-linked matrix and well-oriented CNFs render the resultant aerogels high tensile strength, thus addressing a fundamental and ground challenge in the field of aerogels.
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| 研究実績の概要 |
We have discovered a new, facile, scalable and controllable method to get cellulose nanofibril colloids at any concentrations, using controlled condensation method. All of the condensed CNF materials are highly homogeneous. Further gelation of the condensed CNF hydrogels by protonation (H+) or coordination (Al3+) affords a series of transparent and strong hydrogels with water content of 70-90%, which exhibit tensile strength and modulus more than 9 MPa and 480 MPa, respectively. The water content, strength and modulus are very close or even superior to those of muscles and cartilages and would very promising in the biomedical applications. When dried by supercritical method, we obtained a series of CNF aerogels which is stretchable over 20%, with tensile strength and modulus reach 8 MPa and 100 MPa, respectively, yet still possess very low thermal conductivity at 19.3 mW/mK. Our aerogels, both strong and super-insulating, set a new region in the Ashby plots regarding strength and thermal conductivity.
We have submitted a patent regarding this project. The related manuscript is now under construction, and will submit to several major journals in materials science.
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