Self-Supported Smart Bacterial Nanocellulose–Phosphotungstic Acid Nanocomposites for Photochromic Applications

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dc.contributor.authorSantos, Moliria V. [UNESP]
dc.contributor.authorBarud, Hernane S.
dc.contributor.authorAlencar, Monica A. S. [UNESP]
dc.contributor.authorNalin, Marcelo [UNESP]
dc.contributor.authorToma, Sérgio H.
dc.contributor.authorAraki, Koiti
dc.contributor.authorBenedetti, Assis V. [UNESP]
dc.contributor.authorMaciel, Indhira O.
dc.contributor.authorFragneaud, Benjamin
dc.contributor.authorLegnani, Cristiano [UNESP]
dc.contributor.authorMolina, Celso
dc.contributor.authorCremona, Marco
dc.contributor.authorRibeiro, Sidney J. L. [UNESP]
dc.contributor.institutionUniversidade Estadual Paulista (Unesp)
dc.contributor.institutionUniversidade de Araraquara
dc.contributor.institutionUniversidade de São Paulo (USP)
dc.contributor.institutionUniversidade Federal de Juiz de Fora (UFJF)
dc.contributor.institutionFederal University of São
dc.contributor.institutionPontifícia Universidade Católica do Rio de Janeiro (PUC-Rio)
dc.date.accessioned2021-06-25T11:03:47Z
dc.date.available2021-06-25T11:03:47Z
dc.date.issued2021-05-13
dc.description.abstractBacterial nanocellulose (BNC) is a natural biopolymer obtained by gram-negative bacteria by means of a green and inexhaustible biotechnological process using glucose as producing source. BCN hydrogels is formed by cellulose nanofibrils that maintain an open network structure, an ideal matrix to produce new class of organic-inorganic nanocomposites (OIN) for multifunctional applications. The polyoxometalates (POMs) are complex molecules with several metallic ions sharing oxide ions, forming a highly symmetrical metal oxide cluster. Phosphotungstic acid (PWA), H3PW12O40 photoreduction process activated under ultraviolet irradiation, promoting color change. In this work, photochromic organic-inorganic nanocomposites were prepared by soaking phosphotungstic acid (H3PW12O40) in wet BNC membranes mats at room temperature. Semi-transparent and free-standing BNC/PWA nanocomposite with paper-like aspect were obtained. BNC network was able to control, stabilize and disperse PWA particles in a narrow nanometric distribution, and FTIR spectra indicated that the primary Keggin structure was also preserved in the nanocomposites, independently on the PWA content. The nanoparticles present a narrow distribution of around 16 nm, independently on the PWA concentration. BNC/PWA nanocomposites showed reversible photochromic behavior characteristic of the equilibrium between different tungsten oxidation states. PWA reduction (W6+→ W5+) and organic matrix oxidation is proposed to occur through a radical process involving the interaction of one electron from the oxygen atom of the PWA and one hydrogen from BNC matrix. The photochromic effect vanishes almost completely after 5 h. This mechanism is real in the presence of oxygen, however, if the membranes are left in nitrogen or under vacuum the blue color remains longer than 45 days. Photo-electrochemical behavior was studied by spectroelectrochemistry measurements. It is worth noting that all processes were still reversible in the timescale of the experiment and color changes were observed in several cycles.en
dc.description.affiliationInstitute of Chemistry São Paulo State University (UNESP)
dc.description.affiliationLaboratório de Biopolímeros e Biomateriais (BioPolMat) Universidade de Araraquara
dc.description.affiliationInstituto de Química – Universidade de São Paulo USP
dc.description.affiliationDepartamento de Física Instituto de Ciências Exatas Universidade Federal de Juiz de Fora (UFJF)
dc.description.affiliationDeparment of Chemistry Federal University of São
dc.description.affiliationDepartamento de Física Pontifícia Universidade Católica do Rio de Janeiro (PUC-Rio)
dc.description.affiliationUnespInstitute of Chemistry São Paulo State University (UNESP)
dc.description.sponsorshipConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
dc.description.sponsorshipFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
dc.description.sponsorshipInstituto Nacional de Fotônica
dc.description.sponsorshipIdFAPESP: 2013/07793-6
dc.description.sponsorshipIdFAPESP: 2013/24725-4
dc.description.sponsorshipIdFAPESP: 2014/12424-2
dc.description.sponsorshipIdFAPESP: 2016/11591-8
dc.description.sponsorshipIdFAPESP: 2018/25512-8
dc.description.sponsorshipIdFAPESP: 2020/04509-9
dc.description.sponsorshipIdInstituto Nacional de Fotônica: 407822/2018-6
dc.identifierhttp://dx.doi.org/10.3389/fmats.2021.668835
dc.identifier.citationFrontiers in Materials, v. 8.
dc.identifier.doi10.3389/fmats.2021.668835
dc.identifier.issn2296-8016
dc.identifier.scopus2-s2.0-85107147395
dc.identifier.urihttp://hdl.handle.net/11449/207950
dc.language.isoeng
dc.relation.ispartofFrontiers in Materials
dc.sourceScopus
dc.subjectbacterial nanocellulose
dc.subjectelectrochromism
dc.subjectphosphotungstic acid
dc.subjectphotochromism
dc.subjectpolyoxometalates
dc.titleSelf-Supported Smart Bacterial Nanocellulose–Phosphotungstic Acid Nanocomposites for Photochromic Applicationsen
dc.typeArtigo

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