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(Referência obtida automaticamente do Web of Science, por meio da informação sobre o financiamento pela FAPESP e o número do processo correspondente, incluída na publicação pelos autores.)

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

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Autor(es):
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Santos, Moliria V. [1] ; Barud, Hernane S. [2] ; Alencar, Monica A. S. [1] ; Nalin, Marcelo [1] ; Toma, Sergio H. [3] ; Araki, Koiti [3] ; Benedetti, Assis V. [1] ; Maciel, Indhira O. [4] ; Fragneaud, Benjamin [4] ; Legnani, Cristiano [1, 4] ; Molina, Celso [5] ; Cremona, Marco [6] ; Ribeiro, Sidney J. L. [1]
Número total de Autores: 13
Afiliação do(s) autor(es):
[1] Sao Paulo State Univ UNESP, Inst Chem, Araraquara, SP - Brazil
[2] Univ Araraquara, Lab Biopolimeros & Biomat BioPolMat, Araraquara, SP - Brazil
[3] Univ Sao Paulo, Inst Quim, Sao Paulo - Brazil
[4] Univ Fed Juiz de Fora UFJF, Inst Ciencias Exatas, Dept Fis, Juiz De Fora - Brazil
[5] Univ Fed Sao Paulo, Dept Chem, UNIFESP, Diadema - Brazil
[6] Pontificia Univ Catolica Rio de Janeiro PUC Rio, Dept Fis, Rio De Janeiro - Brazil
Número total de Afiliações: 6
Tipo de documento: Artigo Científico
Fonte: FRONTIERS IN MATERIALS; v. 8, MAY 13 2021.
Citações Web of Science: 0
Resumo

Bacterial 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. (AU)

Processo FAPESP: 14/12424-2 - Propriedades ópticas de suspensões coloidais e filmes à base de nanoceluloses e lantanídeos
Beneficiário:Moliria Vieira dos Santos
Modalidade de apoio: Bolsas no Brasil - Doutorado
Processo FAPESP: 13/07793-6 - CEPIV - Centro de Ensino, Pesquisa e Inovação em Vidros
Beneficiário:Edgar Dutra Zanotto
Modalidade de apoio: Auxílio à Pesquisa - Centros de Pesquisa, Inovação e Difusão - CEPIDs
Processo FAPESP: 16/11591-8 - Microestruturação com lasers de femtossegundos em biopolímeros de celulose e fibroína: fabricação de dispositivos fotônicos
Beneficiário:Moliria Vieira dos Santos
Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado
Processo FAPESP: 13/24725-4 - Química supramolecular e nanotecnologia
Beneficiário:Henrique Eisi Toma
Modalidade de apoio: Auxílio à Pesquisa - Temático
Processo FAPESP: 18/25512-8 - Plataforma para Cultura de Células Baseada em Biocelulose
Beneficiário:Hernane da Silva Barud
Modalidade de apoio: Auxílio à Pesquisa - Regular
Processo FAPESP: 20/04509-9 - Desenvolvimento de substratos condutores biocompatíveis a base de biocelulose e fibroína de seda para aplicações em implantes de retina
Beneficiário:Sidney José Lima Ribeiro
Modalidade de apoio: Auxílio à Pesquisa - Pesquisador Visitante - Brasil