@article{Oliveira2024,

title = {Combining and concentrating nanocelluloses for cryogels with remarkable strength and wet resilience},

author = {Maria C.S. Oliveira and Diego M. Nascimento and Elisa S. Ferreira and Juliana S. Bernardes},

url = {https://www.sciencedirect.com/science/article/abs/pii/S0144861723012055},

doi = {10.1016/j.carbpol.2023.121740},

issn = {0144-8617},

year  = {2024},

date = {2024-04-00},

urldate = {2024-04-00},

journal = {Carbohydrate Polymers},

volume = {330},

publisher = {Elsevier BV},

abstract = {Cellulose cryogels are promising eco-friendly materials that exhibit low density, high porosity, and renewability. However, the applications of these materials are limited by their lower mechanical and water resistance compared to petrochemical-based lightweight materials. In this work, nanocelluloses were functionalized with cationic and anionic groups, and these nanomaterials were combined to obtain strong and water-resilient cryogels. To prepare the cryogels, anionic and cationic micro- and nanofibrils (CNFs) were produced at three different sizes and combined in various weight ratios, forming electrostatic complexes. The complex phase was concentrated by centrifugation and freeze-dried. Porous and open cellular structures were assembled in all compositions tested (porosity >90 %). Compressive testing revealed that the most resistant cryogels (1.7 MPa) were obtained with equivalent amounts of negatively and positively charged CNFs with lengths between 100 and 1200 nm. The strength at this condition was achieved as CNF electrostatic complexes assembled in thick cells, as observed by synchrotron X-ray tomography. In addition to mechanical strength, electrostatic complexation provided remarkable structural stability in water for the CNF cryogels, without compromising their biodegradability. This route by electrostatic complexation is a practical strategy to combine and concentrate nanocelluloses to tailor biodegradable lightweight materials with high strength and wet stability.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Silva2023c,

title = {Enhancing Water Resistance in Cationic Cellulose Nanofibril Adhesive with Natural Rubber Latex},

author = {Daiane B. Silva and Diego M. Nascimento and Pedro I. C. Claro and Rubia F. Gouveia and Juliana S. Bernardes},

url = {https://pubs.acs.org/doi/abs/10.1021/acsanm.3c04257},

doi = {10.1021/acsanm.3c04257},

issn = {2574-0970},

year  = {2024},

date = {2024-01-12},

urldate = {2024-01-12},

journal = {ACS Appl. Nano Mater.},

volume = {7},

number = {1},

pages = {195--204},

publisher = {American Chemical Society (ACS)},

abstract = {Adhesives prepared with renewable materials through environmentally friendly processing offer an appealing alternative to their petroleum-based counterparts. Herein, we evaluated the adhesive properties of cationic cellulose nanofibrils (CCNFs) under dry and wet conditions and after mixing with natural rubber latex (NRL). Uniaxial tensile tests of negatively charged substrates (paper, aluminum (Al), and polypropylene (PP)) bonded with CCNF show a maximum lap shear strength that approached the failure point of the substrates, indicating the formation of a robust adhesive joint. The wet adhesion of CCNFs was improved (53% for PP and 154% for Al) by simple aqueous mixing with NRL suspension. This straightforward methodology promotes controlled CCNF and NRL electrostatic assembly that reduces the swelling of nanofibrils by water and improves adhesive cohesion. Cryogenic transmission electron microscopy images of CCNF/NRL complexes reveal that NRL particles are coated by a fibrillar CCNF network, providing morphological evidence that cationic nanofibrils contribute to interfacial adhesion to the solid substrates, while NRL enhances water resistance. This study presents a simple method to control noncovalent interactions and prepare nanocellulose-based adhesives with good mechanical properties and improved water resistance that are suitable for developing adhesives for different fields.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{CarneiroPessan2023,

title = {Oxidized cellulose nanofibers from sugarcane bagasse obtained by microfluidization: Morphology and rheological behavior},

author = {Cibele Carneiro Pessan and Juliana S. Bernardes and Sílvia H.P. Bettini and Edson R. Leite},

url = {https://www.sciencedirect.com/science/article/abs/pii/S0144861722014102},

doi = {10.1016/j.carbpol.2022.120505},

issn = {0144-8617},

year  = {2023},

date = {2023-03-00},

urldate = {2023-03-00},

journal = {Carbohydrate Polymers},

volume = {304},

publisher = {Elsevier BV},

abstract = {It is advantageous to understand the relationship between cellulose fiber morphology and the rheological behavior of its dispersions so that their application can be optimized. The goal of this study was to produce sugarcane bagasse-sourced cellulose dispersions with different numbers of high-pressure homogenization cycles. Microfluidization produced cellulose nanofibers (between 5 and 80 nm in diameter) with similar surface charge densities and crystallinities (measured on the resulting films). Oscillatory rheology showed that TEMPO-oxidized cellulose dispersions exhibited gel-like behavior. However, not only did the samples with more microfluidization cycles present a lower storage modulus, but the sample with 100 cycles completely lost the gel-like characteristic, presenting a viscous fluid rheological behavior. Thixotropy loop tests revealed the influence of nanofiber length on the dispersion's structure, as evidenced by the decrease in the hysteresis value along with fiber breakage. Therefore, our findings demonstrate that the rheological properties of the dispersion can be tuned according to the length of the nanofibers, allowing for targeted applications.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Silva2023b,

title = {Stabilizing both oil droplets and titanium dioxide nanoparticles in aqueous dispersion with nanofibrillated cellulose},

author = {Caroline E.P. Silva and Juliana S. Bernardes and Watson Loh},

url = {https://www.sciencedirect.com/science/article/pii/S0144861722012590},

doi = {10.1016/j.carbpol.2022.120354},

issn = {0144-8617},

year  = {2023},

date = {2023-02-00},

urldate = {2023-02-00},

journal = {Carbohydrate Polymers},

volume = {302},

publisher = {Elsevier BV},

abstract = {Nanocellulose is a well-known stabilizer for several colloidal dispersions, including emulsions and solid nanoparticles, replacing surfactants, polymers, and other additives, and therefore providing more minimalistic and eco-friendly formulations. However, could this ability be extended to stabilize oil droplets and inorganic nanoparticles simultaneously in the same colloidal system? This work aimed to answer this question. We evaluated both cationic and anionic nanofibrillated celluloses to stabilize both titanium dioxide nanoparticles and oil droplets. The resulting suspensions held their macroscopic stability for up to 2 months, regardless of pH or surface charge. Cryo-TEM images revealed a complex network formation involving nanofibers and TiO2 nanoparticles, which agrees with the high viscosity values and gel-like behavior found in rheology measurements. We propose that the formation of this network is responsible for the simultaneous stabilization of oil droplets and TiO2 nanoparticles, and that this may be used as a formulation tool for other complex systems.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Silvestre2023b,

title = {Nanoscale structural and electronic properties of cellulose/graphene interfaces},

author = {G. H. Silvestre and F. Crasto de Lima and Juliana S. Bernardes and A. Fazzio and R. H. Miwa},

url = {https://pubs.rsc.org/en/content/articlelanding/2022/cp/d2cp04146d/unauth},

doi = {10.1039/d2cp04146d},

issn = {1463-9084},

year  = {2023},

date = {2023-01-04},

urldate = {2023-01-04},

journal = {Phys. Chem. Chem. Phys.},

volume = {25},

number = {2},

pages = {1161--1168},

publisher = {Royal Society of Chemistry (RSC)},

abstract = {The development of electronic devices based on the functionalization of (nano)cellulose platforms relies upon an atomistic understanding of the structural and electronic properties of a combined system, cellulose/functional element. In this work, we present a theoretical study of the nanocellulose/graphene interfaces (nCL/G) based on first-principles calculations. We find that the binding energies of both hydrophobic/G (nCLphob/G) and hydrophilic/G (nCLphil/G) interfaces are primarily dictated by the van der Waals interactions, and are comparable with those of their 2D interface counterparts. We verify that the energetic preference of nCLphob/G has been reinforced by the inclusion of an aqueous medium via an implicit solvation model. Further structural characterization was carried out using a set of simulations of the carbon K-edge X-ray absorption spectra to identify and distinguish the key absorption features of the nCLphob/G and nCLphil/G interfaces. The electronic structure calculations reveal that the linear energy bands of graphene lie in the band gap of the nCL sheet, while depletion/accumulation charge density regions are observed. We show that external agents, i.e., electric field and mechanical strain, allow for tunability of the Dirac cone and charge density at the interface. The control/maintenance of the Dirac cone states in nCL/G is an important feature for the development of electronic devices based on cellulosic platforms.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Pessan2023,

title = {Self-sustained Films of Cellulose/Graphite Composites: Mechanical and Water Vapor Barrier Properties},

author = {Cibele Carneiro Pessan and Juliana S. Bernardes and Sílvia H. P. Bettini and Edson R. Leite},

url = {https://www.scielo.br/j/mr/a/g8cgZpQpybCJjYhp4PZpPpQ/?format=html&lang=en},

doi = {10.1590/1980-5373-mr-2023-0046},

issn = {1980-5373},

year  = {2023},

date = {2023-00-00},

urldate = {2023-00-00},

journal = {Mat. Res.},

volume = {26},

number = {suppl 1},

publisher = {FapUNIFESP (SciELO)},

abstract = {Cellulosic materials have several applications, from rheological modifiers to structural reinforcement and packaging components. Using cellulosic materials may also contribute to environmental sustainability because it can be sourced from agricultural byproducts. In this work, self-sustained composite films were produced by the casting of TEMPO-oxidized cellulose nanofibers/graphite composite dispersions. Oscillatory rheology and tensile strength tests showed that the presence of graphite did not significantly contribute to the enhancement of neither the rheological nor mechanical properties of the dispersions and films. Morphological analysis showed that particle segregation and setting occurred during film casting, resulting in particle concentration gradient along the thickness of the film. These results could indicate the low exfoliation efficiency of the microfluidization process and, therefore, justify why the graphite did not act as a reinforcement of the cellulose matrix. However, the graphite particles contributed to a higher barrier to water vapor permeation of the cellulosic films.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Nascimento2022d,

title = {How lignin sticks to cellulose—insights from atomic force microscopy enhanced by machine-learning analysis and molecular dynamics simulations},

author = {Diego M. Nascimento and Felippe M. Colombari and Bruno Focassio and Gabriel R. Schleder and Carlos A. R. Costa and Cleyton A. Biffe and Liu Y. Ling and Rubia F. Gouveia and Mathias Strauss and George J. M. Rocha and Edson Leite and Adalberto Fazzio and Rodrigo B. Capaz and Carlos Driemeier and Juliana S. Bernardes},

url = {https://pubs.rsc.org/en/content/articlelanding/2022/nr/d2nr05541d/unauth},

doi = {10.1039/d2nr05541d},

issn = {2040-3372},

year  = {2022},

date = {2022-12-08},

urldate = {2022-12-08},

journal = {Nanoscale},

volume = {14},

number = {47},

pages = {17561--17570},

publisher = {Royal Society of Chemistry (RSC)},

abstract = {Elucidating cellulose–lignin interactions at the molecular and nanometric scales is an important research topic with impacts on several pathways of biomass valorization. Here, the interaction forces between a cellulosic substrate and lignin are investigated. Atomic force microscopy with lignin-coated tips is employed to probe the site-specific adhesion to a cellulose film in liquid water. Over seven thousand force-curves are analyzed by a machine-learning approach to cluster the experimental data into types of cellulose-tip interactions. The molecular mechanisms for distinct types of cellulose–lignin interactions are revealed by molecular dynamics simulations of lignin globules interacting with different cellulose Iβ crystal facets. This unique combination of experimental force-curves, data-driven analysis, and molecular simulations opens a new approach of investigation and updates the understanding of cellulose–lignin interactions at the nanoscale.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Fingolo2021,

title = {Enhanced Hydrophobicity in Nanocellulose-Based Materials: Toward Green Wearable Devices},

author = {Ana C. Fingolo and Vitória B. de Morais and Saionara V. Costa and Cátia C. Corrêa and Beatriz Lodi and Murilo Santhiago and Juliana S. Bernardes and Carlos C. B. Bufon},

url = {https://pubs.acs.org/doi/abs/10.1021/acsabm.1c00317},

doi = {10.1021/acsabm.1c00317},

issn = {2576-6422},

year  = {2021},

date = {2021-09-20},

urldate = {2021-09-20},

journal = {ACS Appl. Bio Mater.},

volume = {4},

number = {9},

pages = {6682--6689},

publisher = {American Chemical Society (ACS)},

abstract = {Nanocellulose is a promising material for fabricating green, biocompatible, flexible, and foldable devices. One of the main issues of using nanocellulose as a fundamental component for wearable electronics is the influence of environmental conditions on it. The water adsorption promotes the swelling of nanopaper substrates, which directly affects the devices’ electrical properties prepared on/with it. Here, plant-based nanocellulose substrates, and ink composites deposited on them, are chemically modified using hexamethyldisilazane to enhance the system’s hydrophobicity. After the treatment, the electrical properties of the devices exhibit stable operation under humidity levels around 95%. Such stability demonstrates that the hexamethyldisilazane modification substantially suppresses the water adsorption on fundamental device structures, namely, substrate plus conducting ink. These results attest to the robustness necessary to use nanocellulose as a key material in wearable devices such as electronic skins and tattoos and contribute to the worldwide efforts to create biodegradable devices engineered in a more deterministic fashion.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Fingolo2021b,

title = {Enhanced Hydrophobicity in Nanocellulose-Based Materials: Toward Green Wearable Devices},

author = {Ana C. Fingolo and Vitória B. de Morais and Saionara V. Costa and Cátia C. Corrêa and Beatriz Lodi and Murilo Santhiago and Juliana S. Bernardes and Carlos C. B. Bufon},

url = {https://pubs.acs.org/doi/abs/10.1021/acsabm.1c00317},

doi = {10.1021/acsabm.1c00317},

issn = {2576-6422},

year  = {2021},

date = {2021-09-20},

urldate = {2021-09-20},

journal = {ACS Appl. Bio Mater.},

volume = {4},

number = {9},

pages = {6682--6689},

publisher = {American Chemical Society (ACS)},

abstract = {Nanocellulose is a promising material for fabricating green, biocompatible, flexible, and foldable devices. One of the main issues of using nanocellulose as a fundamental component for wearable electronics is the influence of environmental conditions on it. The water adsorption promotes the swelling of nanopaper substrates, which directly affects the devices’ electrical properties prepared on/with it. Here, plant-based nanocellulose substrates, and ink composites deposited on them, are chemically modified using hexamethyldisilazane to enhance the system’s hydrophobicity. After the treatment, the electrical properties of the devices exhibit stable operation under humidity levels around 95%. Such stability demonstrates that the hexamethyldisilazane modification substantially suppresses the water adsorption on fundamental device structures, namely, substrate plus conducting ink. These results attest to the robustness necessary to use nanocellulose as a key material in wearable devices such as electronic skins and tattoos and contribute to the worldwide efforts to create biodegradable devices engineered in a more deterministic fashion.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Silvestre2021b,

title = {Disassembly of TEMPO-Oxidized Cellulose Fibers: Intersheet and Interchain Interactions in the Isolation of Nanofibers and Unitary Chains},

author = {Gustavo H. Silvestre and Lidiane O. Pinto and Juliana S. Bernardes and Roberto H. Miwa and Adalberto Fazzio},

url = {https://pubs.acs.org/doi/abs/10.1021/acs.jpcb.1c01928},

doi = {10.1021/acs.jpcb.1c01928},

issn = {1520-5207},

year  = {2021},

date = {2021-04-15},

urldate = {2021-04-15},

journal = {J. Phys. Chem. B},

volume = {125},

number = {14},

pages = {3717--3724},

publisher = {American Chemical Society (ACS)},

abstract = {Cellulose disassembly is an important issue in designing nanostructures using cellulose-based materials. In this work, we present a combination of experimental and theoretical study addressing the disassembly of cellulose nanofibrils. Through 2,2,6,6-tetramethylpiperidine-1-oxyl-mediated oxidation processes, combined with atomic force microscopy results, we show the formation of nanofibers with diameters corresponding to that of a single-cellulose polymer chain. The formation of these polymer chains is controlled by repulsive electrostatic interactions between the oxidized chains. Further, first-principles calculations have been performed in order to provide an atomistic understanding of the cellulose disassembling processes, focusing on the balance between the interchain (IC) and intersheet (IS) interactions upon oxidation. First, we analyze these interactions in pristine systems, where we found the IS interaction to be stronger than the IC interaction. In the oxidized systems, we have considered the formation of (charged) carboxylate groups along the inner sites of elementary fibrils. We show a net charge concentration on the carboxylate groups, supporting the emergence of repulsive electrostatic interactions between the cellulose nanofibers. Indeed, our total energy results show that the weakening of the binding strength between the fibrils is proportional to the concentration and net charge density of the carboxylate group. Moreover, by comparing the IC and IS binding energies, we found that most of the disassembly processes should take place by breaking the IC O–H···O hydrogen bond interactions and thus supporting the experimental observation of single- and double-cellulose polymer chains.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Mariano2021,

title = {Tailoring strength of nanocellulose foams by electrostatic complexation},

author = {Marcos Mariano and Sivoney F. Souza and Antônio C. Borges and Diego M. do Nascimento and Juliana S. Bernardes},

url = {https://www.sciencedirect.com/science/article/abs/pii/S0144861720317203},

doi = {10.1016/j.carbpol.2020.117547},

issn = {0144-8617},

year  = {2021},

date = {2021-03-00},

urldate = {2021-03-00},

journal = {Carbohydrate Polymers},

volume = {256},

publisher = {Elsevier BV},

abstract = {Supramolecular assembly of biobased components in water is a promising strategy to construct advanced materials. Herein, electrostatic complexation was used to prepare wet-resilient foams with improved mechanical property. Small-angle X-ray scattering and cryo-transmission electron microscopy experiments showed that suspensions with oppositely charged cellulose nanofibers are a mixture of clusters and networks of entangled fibers. The balance between these structures governs the colloidal stability and the rheological behavior of CNFs in water. Foams prepared from suspensions exhibited maximum compressive modulus at the mass composition of 1:1 (ca 0.12 MPa), suggesting that meaningful attractive interactions happen at this point and act as stiffening structure in the material. Besides the electrostatic attraction, hydrogen bonds and hydrophobic contacts may also occur within the clustering, improving the water stability of cationic foams. These results may provide a basis for the development of robust all- cellulose materials prepared in water, with nontoxic chemicals.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}