Browsing by Author "Zhao, Bin"

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All-Aqueous Liquid Crystal Nanocellulose Emulsions with Permeable Interfacial Assembly
(2020-10-27) Bai, Long; Huan, Siqi; Zhao, Bin; Zhu, Ya; Esquena, Jordi; Chen, Feng; Gao, Guang; Zussman, Eyal; Chu, Guang; Rojas, Orlando J.
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
We report on the formation of water-in-water liquid crystal emulsions with permeable colloidal assemblies. Rodlike cellulose nanocrystals (CNC) spontaneously self-assemble into a helical arrangement with the coexistence of nonionic, hydrophilic polyethylene glycol (PEG) and dextran, whereas the two polymer solutions are thermodynamically incompatible. Stable water-in-water emulsions are easily prepared by mixing the respective CNC/polymer solutions, showing micrometric CNC/PEG dispersed droplets and a continuous CNC/dextran phase. With time, the resulting emulsion demixes into an upper, droplet-lean isotropic phase and a bottom, droplet-rich cholesteric phase. Owing to the osmotic pressure gradient between PEG and dextran phases, target transfer of cellulose nanoparticles occurs across the water/water interface to reassemble into a liquid crystal-in-liquid crystal emulsion with global cholesteric organization. The observed structural, optical, and temporal evolution confirm that the colloidal particles in the two immiscible phases experience short-range interactions and form long-range assemblies across the interface.
Endoglucanase effects on energy consumption in the mechanical fibrillation of cellulose fibers into nanocelluloses
(2023-07-15) Berto, Gabriela L.; Mattos, Bruno D.; Velasco, Josman; Zhao, Bin; Segato, Fernando; Rojas, Orlando J.; Arantes, Valdeir
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Enzymatic processing is considered a promising approach for advancing environmentally friendly industrial processes, such as the use of endoglucanase (EG) enzyme in the production of nanocellulose. However, there is ongoing debate regarding the specific properties that make EG pretreatment effective in isolating fibrillated cellulose. To address this issue, we investigated EGs from four glycosyl hydrolase (GH) families (5, 6, 7, and 12) and examined the roles of the three-dimensional structure and catalytic features, with a focus on the presence of a carbohydrate binding module (CBM). Using eucalyptus Kraft wood fibers, we produced cellulose nanofibrils (CNFs) through mild enzymatic pretreatment, followed by disc ultra-refining. Comparing the results with the control (without pretreatment), we observed that GH5 and GH12 enzymes (without CBM) reduced fibrillation energy by approximately 15 %. The most significant energy reduction, 25 and 32 %, was achieved with GH5 and GH6 linked to CBM, respectively. Notably, these CBM-linked EGs improved the rheological properties of CNF suspensions without releasing soluble products. In contrast, GH7-CBM exhibited significant hydrolytic activity, resulting in the release of soluble products, but did not contribute to a reduction in fibrillation energy. This discrepancy can be attributed to the large molecular weight and wide cleft of GH7-CBM, which led to the release of soluble sugars but had little impact on fibrillation. Our findings suggest that the improved fibrillation observed with EG pretreatment is primarily driven by efficient enzyme adsorption on the substrate and modification of the surface viscoelasticity (amorphogenesis), rather than hydrolytic activity or release of products.
Form-stable phase change materials from mesoporous balsa after selective removal of lignin
(2020-10-15) Meng, Yang; Majoinen, Johanna; Zhao, Bin; Rojas Gaona, Orlando
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
We produce balsa-based structures by selective removal of lignin. The changes that occur in the main components of balsa upon delignification, including tracheids, closed pits and tylosis vessels, allow the development of mesopores and a substantial increase in fluid permeability. Such system is ideally suited as a support of phase change materials, PCM. Vacuum-assisted impregnation with polyethylene glycol (PEG, a PCM), results in a form-stable PCM system (FPCM). The FPCM displays a high encapsulating capacity (83.5%) at temperatures above the melting PEG transition, with a latent heat of 134 J/g and low supercooling (12 °C). The results are rationalized by the affinity between the unidirectional mesoporous structure and the polymer, involving capillary forces and hydrogen bonding. The leakage-proof FPCM outperforms available systems (based on PEG or other PCMs) supported on minerals or other wood species. Compared to the latter group, the results obtained with balsa relate with its morphology and the effect of residual hemicelluloses in hierarchically-aligned cellulose nano- and microfibrils. The FPCMs resist compressive loads and performs stably for at least 200 cycles of heating and cooling. An insignificant loss in latent heat is observed compared to that of pure PEG. The phase transition temperature fluctuation and non-leaking characteristics under load make the balsa-based FPCM a superior alternative for passive heating/cooling, especially for uses at high ambient temperatures. The reversible thermoregulatory capacity, low cost, high efficiency, renewability, and operability of the balsa-supported FPCM, indicate an excellent option for thermal energy storage and conversion devices.
Interfacial Membranization of Regenerated Cellulose Nanoparticles and a Protein Renders Stable Water-in-Water Emulsion
(2024-11-01) Zhu, Ya; Beaumont, Marco; Solin, Katariina; Spiliopoulos, Panagiotis; Zhao, Bin; Tao, Han; Kontturi, Eero; Bai, Long; Rojas, Orlando J.
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Pickering water-in-water (W/W) emulsions stabilized by biobased colloids are pertinent to engineering biomaterials with hierarchical and confined architectures. In this study, stable W/W emulsions are developed through membranization utilizing biopolymer structures formed by the adsorption of cellulose II nanospheres and a globular protein, bovine serum albumin (BSA), at droplet surfaces. The produced cellulose II nanospheres (NPcat, 63 nm diameter) bearing a soft and highly accessible shell, endow rapid and significant binding (16 mg cm−2) with BSA. NPcat and BSA formed complexes that spontaneously stabilized liquid droplets, resulting in stable W/W emulsions. It is proposed that such a system is a versatile all-aqueous platform for encapsulation, (bio)catalysis, delivery, and synthetic cell mimetics.
Lignin-Based Porous Supraparticles for Carbon Capture
(2021-04-27) Zhao, Bin; Borghei, Maryam; Zou, Tao; Wang, Ling; Johansson, Leena-Sisko; Majoinen, Johanna; Sipponen, Mika H.; Österberg, Monika; Mattos, Bruno D.; Rojas, Orlando J.
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Multiscale carbon supraparticles (SPs) are synthesized by soft-templating lignin nano- and microbeads bound with cellulose nanofibrils (CNFs). The interparticle connectivity and nanoscale network in the SPs are studied after oxidative thermostabilization of the lignin/CNF constructs. The carbon SPs are formed by controlled sintering during carbonization and develop high mechanical strength (58 N·mm-3) and surface area (1152 m2·g-1). Given their features, the carbon SPs offer hierarchical access to adsorption sites that are well suited for CO2 capture (77 mg CO2·g-1), while presenting a relatively low pressure drop (∼33 kPa·m-1 calculated for a packed fixed-bed column). The introduced lignin-derived SPs address the limitations associated with mass transport (diffusion of adsorbates within channels) and kinetics of systems that are otherwise based on nanoparticles. Moreover, the carbon SPs do not require doping with heteroatoms (as tested for N) for effective CO2 uptake (at 1 bar CO2 and 40 °C) and are suitable for regeneration, following multiple adsorption/desorption cycles. Overall, we demonstrate porous SP carbon systems of low cost (precursor, fabrication, and processing) and superior activity (gas sorption and capture).
Monodispersed Renewable Particles by Cascade and Density Gradient Size Fractionation to Advance Lignin Nanotechnologies
(2024-08-22) Chen, Jingqian; Tian, Jing; Feng, Nianjie; Ning, Like; Wang, Dong; Zhao, Bin; Guo, Tianyu; Song, Junlong; Rojas, Orlando J.
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Control over particle size and shape heterogeneity is highly relevant to the design of photonic coatings and supracolloidal assemblies. Most developments in the area have relied on mineral and petroleum-derived polymers that achieve well-defined chemical and dimensional characteristics. Unfortunately, it is challenging to attain such control when considering renewable nanoparticles. Herein, a pathway toward selectable biobased particle size and physicochemical profiles is proposed. Specifically, lignin is fractionated, a widely available heterogeneous polymer that can be dissolved in aqueous solution, to obtain a variety of monodispersed particle fractions. A two-stage cascade and density gradient centrifugation that relieves the need for solvent pre-extraction or other pretreatments but achieves particle bins of uniform size (~60 to 860 nm and polydispersity, PDI<0.06, dynamic light scattering) along with characteristic surface chemical features is introduced. It is found that the properties and associated colloidal behavior of the particles are suitably classified in distinctive size populations, namely, i) nanoscale (50–100 nm), ii) photonic (100–300 nm) and iii) near-micron (300–1000 nm). The strong correlation that exists between size and physicochemical characteristics (molar mass, surface charge, bonding and functional groups, among others) is introduced as a powerful pathway to identify nanotechnological uses that benefit from the functionality and cost-effectiveness of biogenic particles.
Nanocellulose Removes the Need for Chemical Crosslinking in Tannin-Based Rigid Foams and Enhances Their Strength and Fire Retardancy
(2022-08-08) Missio, André Luiz; Otoni, Caio G.; Zhao, Bin; Beaumont, Marco; Khakalo, Alexey; Kämäräinen, Tero; Silva, Silvia H.F.; Mattos, Bruno D.; Rojas, Orlando J.
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Thermal insulation and fire protection are two of the most critical features affecting energy efficiency and safety in built environments. Together with the associated environmental footprint, there is a strong need to consider new insulation materials. Tannin rigid foams have been proposed as viable and sustainable alternatives to expanded polyurethanes, traditionally used in building enveloping. Tannin foams structure result from polymerization with furfuryl alcohol via self-expanding. We further introduce cellulose nanofibrils (CNFs) as a reinforcing agent that eliminates the need for chemical crosslinking during foam formation. CNF forms highly entangled and interconnected nanonetworks, at solid fractions as low as 0.1 wt %, enabling the formation of foams that are ca. 30% stronger and ca. 25% lighter compared to those produced with formaldehyde, currently known as one of the best performers in chemically coupling tannin and furfuryl alcohol. Compared to the those chemically crosslinked, our CNF-reinforced tannin foams display higher thermal degradation temperature (peak shifted upward, by 30-50 °C) and fire resistance (40% decrease in mass loss). Furthermore, we demonstrate partially hydrophobized CNF to tailor the foam microstructure and derived physical-mechanical properties. In sum, green and sustainable foams, stronger, lighter, and more resistant to fire are demonstrated compared to those produced by formaldehyde crosslinking.
Nanostructured single-atom catalysts derived from natural building blocks
(2024-03-01) Zhang, Yajing; Yang, Guobin; Wang, Jin; Zhao, Bin; He, Yunxiang; Guo, Junling
A2 Katsausartikkeli tieteellisessä aikakauslehdessä
Single-atom catalysts (SACs) exhibit maximized atomic utilization with individual metal atoms anchored on supporting materials, where the pursuit of high performance and low cost presents challenges. In this case, carbon provides structural versatility and customizable properties as a supporting material, which has been extensively studied. Biomass materials have emerged as promising precursors for the preparation of carbon-based SACs due to their renewable nature for sustainability, abundance for low cost, and high carbon content for advanced performance. In this review, representative synthesis strategies and advanced characterization techniques for biomass-derived CS-SACs are summarized, which facilitate the establishment of guidelines for the rational design and fabrication of biomass-derived SACs. In addition, we provide a timely and comprehensive discussion on the use of a broad range of natural biomass for SACs, with insights into the specific carbon nature of biomass resources, including their carbon structures, metal-carbon coordination environment, and center metal species. Furthermore, the application areas of biomass-derived CS-SACs in various catalytic processes are reviewed. Overall, the challenges and future perspectives of using biomass as precursors for SACs are outlined. We hope that this review can offer a valuable overview of the current knowledge, recent progress, and directions of biomass-derived SACs.
Regioselective and water-assisted surface esterification of never-dried cellulose: nanofibers with adjustable surface energy
(2021-09-21) Beaumont, Marco; Otoni, Caio G.; Mattos, Bruno D.; Koso, Tetyana V.; Abidnejad, Roozbeh; Zhao, Bin; Kondor, Anett; King, Alistair W. T.; Rojas, Orlando J.
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
A new regioselective route is introduced for surface modification of biological colloids in the presence of water. Taking the case of cellulose nanofibers (CNFs), we demonstrate a site-specific (93% selective) reaction between the primary surface hydroxyl groups (C6-OH) of cellulose and acyl imidazoles. CNFs bearing C6-acetyl and C6-isobutyryl groups, with a degree of substitution of up to 1 mmol g(-1) are obtained upon surface esterification, affording CNFs of adjustable surface energy. The morphological and structural features of the nanofibers remain largely unaffected, but the regioselective surface reactions enable tailoring of their interfacial interactions, as demonstrated in oil/water Pickering emulsions. Our method precludes the need for drying or exchange with organic solvents for surface esterification, otherwise needed in the synthesis of esterified colloids and polysaccharides. Moreover, the method is well suited for application at high-solid content, opening the possibility for implementation in reactive extrusion and compounding. The proposed acylation is introduced as a sustainable approach that benefits from the presence of water and affords a high chemical substitution selectivity.
Self-Assembled Nanorods and Microspheres for Functional Photonics : Retroreflector Meets Microlens Array
(2021-05-05) Chu, Guang; Chen, Feng; Zhao, Bin; Zhang, Xue; Zussman, Eyal; Rojas, Orlando J.
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Patterned micro/nanomaterials display efficient light management capabilities owing to their control of light propagation within multiscale periodic structures. Here a hierarchical photonic structure composed of polystyrene microspheres and cholesteric assembly of cellulose nanocrystals is described, acting as a polarization-sensitive retroreflective coating and microlens array. Micropatterned photonic films are prepared by casting an aqueous cellulose nanocrystal suspension onto a monolayer of polystyrene microspheres substrate through evaporation-assisted transfer imprinting lithography, integrating a bulk cholesteric matrix and patterned surface. By directing light at the as-assembled polystyrene surface, an enhanced structural color develops from the circularly polarized light retroreflection. Whereas when light travelling across the photonic film, the transparent layer of polystyrene microspheres forms into plano-convex microlens to converge the transmitted light into the focus plane and reduce centimeter-scale illuminated image into a high-fidelity miniaturized replica. This simple method, combining self-assembly with imprinting lithography, is expected to pave the way for designing custom-tailored optics with novel functions.
Wood-based superblack
(2023-12-05) Zhao, Bin; Shi, Xuetong; Khakalo, Sergei; Meng, Yang; Miettinen, Arttu; Turpeinen, Tuomas; Mi, Shuyi; Sun, Zhipei; Khakalo, Alexey; Rojas Gaona, Orlando; Dufau Mattos, Bruno
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Light is a powerful and sustainable resource, but it can be detrimental to the performance and longevity of optical devices. Materials with near-zero light reflectance, i.e. superblack materials, are sought to improve the performance of several light-centered technologies. Here we report a simple top-down strategy, guided by computational methods, to develop robust superblack materials following metal-free wood delignification and carbonization (1500 °C). Subwavelength severed cells evolve under shrinkage stresses, yielding vertically aligned carbon microfiber arrays with a thickness of ~100 µm and light reflectance as low as 0.36% and independent of the incidence angle. The formation of such structures is rationalized based on delignification method, lignin content, carbonization temperature and wood density. Moreover, our measurements indicate a laser beam reflectivity lower than commercial light stoppers in current use. Overall, the wood-based superblack material is introduced as a mechanically robust surrogate for microfabricated carbon nanotube arrays.