Hydroxyl groups on cellulose nanocrystal surfaces form nucleation points for silver nanoparticles of varying shapes and sizes

• Published in: Journal of colloid and interface science Vol. 584; pp. 360 - 371
• Main Authors: Musino, Dafne, Rivard, Camille, Landrot, Gautier, Novales, Bruno, Rabilloud, Thierry, Capron, Isabelle
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 15-02-2021; Elsevier
• Subjects: AgNP size-shape variation; Bacterial cellulose nanocrystal (BCN); Chemical Sciences; Hybrid nanomaterial; Hydrophobic BCN; Hydroxyl groups; Material chemistry; Polymers; Silver nanoparticles (AgNPs); Surface modification; Surface modification; Silver nanoparticles (AgNPs); Hydrophobic BCN; Hybrid nanomaterial; AgNP size-shape variation; Bacterial cellulose nanocrystal (BCN); Hydroxyl groups
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/j.jcis.2020.09.082

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In this study, we investigate the interactions between the cellulose surface and Ag nanoparticles (AgNPs) for the purpose of manufacturing hybrid nanomaterials using bacterial cellulose nanocrystals (BCNs) as a model substrate. We focus on the role of the BCN surface chemistry on the AgNP nucleation obtained by chemical reduction of Ag+ ions. Homogeneous hybrid suspensions of BCN/AgNP are produced, regardless of whether the BCNs are quasi-neutral, negatively (TBCNs) or positively charged (ABCNs). The characterization of BCN/AgNP hybrids identifies the –OH surface groups as nucleation points for AgNPs, of about 20 nm revealing that surface charges only improve the accessibility to OH groups. X-ray Absorption technics (XANES and EXAFS) revealed a high metallic Ag0 content ranging from 88% to 97%. Moreover, the grafting of hydrophobic molecules on a BCN surface (HBCNs) does not prevent AgNP nucleation, illustrating the versatility of our method and the possibility to obtain bifunctional NPs. A H2O2 redox post-treatment on the hybrid induces an increase in AgNPs size, up to 90 nm as well as a shape variation (i.e., triangular). In contrast, H2O2 induces no size/shape variation for aggregated hybrids, emphasizing that the accessibility to –OH groups ensures the nucleation of bigger Ag nano-objects.