Controlling superstructure formation and macro-scale adhesion via confined evaporation of cellulose nanocrystals

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A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
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The self-assembly of cellulose nanocrystals can tether their interfacial interactions and the associated properties of their constructs. For instance, assemblies of highly aligned cellulose nanocrystals (CNCs) bear improved mechanical strength, barrier properties, and piezoelectric response. In this study, the self-assembly of CNC superstructure was assessed under various confinement geometries, enabling optimization of the long-range order within the microstructures formed. The confinement involved the planar capillary (with a rectangular cross-section)formed between two glass substrates with silicone boundaries. The impact of temperature, width and thickness of the capillary plane on self-assembly of the micro-scaled lamellar structures was evaluated. Thinner capillaries and lower temperatures were found to considerably improve long-range order and increase the frequency of the periodic microstructures formed. The drying process was monitored by rheological analysis, which showed an initial fast drying followed by slow drying due to the hindered diffusion through lamellae. The adhesive properties of the formed superstructures were evaluated. The shear strength was shown to depend on the orientation of the superstructures and therefore of the CNCs. About 4 MPa adhesion strength was obtained when the lamellar superstructures were perpendicularly aligned with respect to the in-plane force applied, while ca. 3 MPa adhesion was obtained for parallel alignment. The experimental framework described herein enabled the evaluation of the impact of the dimensions of a drying meniscus on self-assembly of anisometric colloids while also linking cellulosic assemblies with their interfacial supramolecular interactions. This simple framework brings forward the possibility to correlate the behavior of nanometric objects with micro- and macro-scaled observations, e.g., macro-scaled mechanics of adhesion.
| openaire: EC/H2020/788489/EU//BioELCell Funding Information: A.M.B-L. acknowledges the Margarita Salas (SOL-RPU-59) grant received and the Ph.D. Research Grant from the Ministerio de Educación, Cultura y Deporte (FPU16/03697). The collaboration with the University of Aalto has been possible thanks to the grants EST17/00875 and EST1/00577 from the Ministerio de Educación y Formación Profesional. L.G.G. acknowledges funding by the Aalto University School of Chemical Engineering doctoral programme. BLT acknowledges Khalifa University of Science and Technology (KUST) for the Faculty Startup Project (Project code: 84741140-FSU-2022-021). OJR acknowledges support by European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement No 788489, “BioElCell”), the Canada Excellence Research Chair Program (CERC-2018-00006) and the Canada Foundation for Innovation (Project number 38623). Publisher Copyright: © 2022, The Author(s).
Adhesion, Cellulose nanocrystals, Confinement, Rheology, Self-assembly, Supramolecular interactions
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Borrero-López, A M, Garcia Greca, L, Rojas, O J & Tardy, B L 2023, ' Controlling superstructure formation and macro-scale adhesion via confined evaporation of cellulose nanocrystals ', Cellulose, vol. 30, no. 2, pp. 741-751 .