Free-standing three-dimensional hollow bacterial cellulose structures with controlled geometry via patterned superhydrophobic–hydrophilic surfaces

Soft Matter ◽  
2018 ◽  
Vol 14 (19) ◽  
pp. 3955-3962 ◽  
Author(s):  
Anna Laromaine ◽  
Tina Tronser ◽  
Ivana Pini ◽  
Sebastià Parets ◽  
Pavel A. Levkin ◽  
...  

Biosynthesis of multiple shapes of 3D self-standing BC structures in a static one-step process to fabricate advanced materials.

2016 ◽  
Vol 4 (35) ◽  
pp. 13589-13602 ◽  
Author(s):  
Dandan Shan ◽  
Jiao Yang ◽  
Wei Liu ◽  
Jun Yan ◽  
Zhuangjun Fan

3D honeycomb-like hierarchical structured carbon (HSC) has been fabricated by one-step carbonization/activation of abundant and low cost bacterial cellulose for ultrahigh energy density supercapacitors.


2020 ◽  
Vol 26 (45) ◽  
pp. 5793-5806
Author(s):  
Mazhar Ul-Islam ◽  
Salman Ul-Islam ◽  
Sumayia Yasir ◽  
Atiya Fatima ◽  
Md. Wasi Ahmed ◽  
...  

Biopolymers and their composites have been extensively investigated in recent years for multiple applications, especially in environmental, medical, and pharmaceutical fields. Bacterial cellulose (BC) has emerged as a novel biomaterial owing to its nontoxic, high-liquid absorbing and holding capacity, drug-carrying ability, and pollutant absorbing features. Additionally, its web-shaped three-dimensional (3D) structure and hydrogen bonding sites have incited a combination of various nanoparticles, polymers, and other materials with BC in the form of composites. Such BC-based composites have been developed through in-situ, ex-situ, and solution casting methods for targeted applications, such as air and water filters, controlled drug delivery systems, wound dressing materials, and tissue regeneration. This review details the production and development of BCbased composites with different materials and by various methods. It further describes various applications of BC-based composites in the environmental and pharmaceutical sectors, with specific examples from the recent literature. This review could potentially appeal a wide readership in these two emerging fields, where novel and advanced materials for different applications have been developed on a regular basis using BC as the base material.


2020 ◽  
Author(s):  
Kristen Miller ◽  
Lawrence B. Alemany ◽  
Edwin L. Thomas ◽  
Eilaf Egap

<p>Two-dimensional (2D) benzoxazole-linked covalent organic frameworks (COFs) provide an opportunity to incorporate the strength and modulus of corresponding 1D rigid-rod polymers into multiple directions by extending covalent bonding into two dimensions while simultaneously reducing density. Thus far, this potential has been elusive because of the challenge of producing high-quality COF films, particularly those with irreversible, rigid benzazole linkages. The majority of COF syntheses use a single-step process approach where polymerization occurs faster than crystallization and typically result in a poorly ordered and insoluble powder. Here, we present a one-step synthesis and two-step process that allows the deposition of a uniform intermediate film via reversible, non-covalent interactions. This network then undergoes an annealing step that facilitates the irreversible conversion to 2D covalently-bonded polymer product. The resulting films are semi-crystalline with platelet-like crystals embedded in an amorphous matrix with sharp crystal-amorphous interfaces. By this approach, we achieve free-standing films for which we demonstrate the first example of mechanical testing of benzazole-linked COFs. These initial films have promising mechanical properties with an in-plane ultimate tensile strength of nearly 50 MPa and axial tensile and transverse compressive elastic moduli on the scale of several GPa. These mechanical properties already rival the performance of solution-cast films of 1D polybenzoxazole (PBO).<i></i></p>


RSC Advances ◽  
2015 ◽  
Vol 5 (60) ◽  
pp. 48875-48880 ◽  
Author(s):  
Yizao Wan ◽  
Zhiwei Yang ◽  
Guangyao Xiong ◽  
Sudha R. Raman ◽  
Honglin Luo

Free-standing silica nanotubes with a three-dimensional network structure were prepared via a template-assisted sol–gel process by using bacterial cellulose as a template and catalyst and for calcination.


2020 ◽  
Author(s):  
Kristen Miller ◽  
Lawrence B. Alemany ◽  
Edwin L. Thomas ◽  
Eilaf Egap

<p>Two-dimensional (2D) benzoxazole-linked covalent organic frameworks (COFs) provide an opportunity to incorporate the strength and modulus of corresponding 1D rigid-rod polymers into multiple directions by extending covalent bonding into two dimensions while simultaneously reducing density. Thus far, this potential has been elusive because of the challenge of producing high-quality COF films, particularly those with irreversible, rigid benzazole linkages. The majority of COF syntheses use a single-step process approach where polymerization occurs faster than crystallization and typically result in a poorly ordered and insoluble powder. Here, we present a one-step synthesis and two-step process that allows the deposition of a uniform intermediate film via reversible, non-covalent interactions. This network then undergoes an annealing step that facilitates the irreversible conversion to 2D covalently-bonded polymer product. The resulting films are semi-crystalline with platelet-like crystals embedded in an amorphous matrix with sharp crystal-amorphous interfaces. By this approach, we achieve free-standing films for which we demonstrate the first example of mechanical testing of benzazole-linked COFs. These initial films have promising mechanical properties with an in-plane ultimate tensile strength of nearly 50 MPa and axial tensile and transverse compressive elastic moduli on the scale of several GPa. These mechanical properties already rival the performance of solution-cast films of 1D polybenzoxazole (PBO).<i></i></p>


2021 ◽  
Author(s):  
Mohamed Elshafei ◽  
Ahmed Gamal El Deen ◽  
Ahmed Abd Elmoneim ◽  
Amr Hessein

Abstract In this work, a versatile one-step hydrothermal technique was used to produce a hybrid standalone electrode of NiCo2O4 hierarchical nanostructures anchored on CNFs mat for highly-performance and substrate-free supercapacitors. The CNFs mat was working as a conductive and a three-dimensional template for hierarchical NiCo2O4 nanostructures deposition at the same time. The morphological and structural data analysis revealed a pure spinel NiCo2O4 nanostructures with a unique surface morphology comprising interconnected ultrathin nanoneedles and nanoflowers were successfully anchored to the CNFs mat. Real supercapacitors consist of two-symmetrical hybrid electrodes with different NiCo2O4 loading ratios were assembled and tested. The electrochemical performances of the assembled devices in terms of specific capacitance, energy, and power densities were systematically evaluated. Increasing the NiCo2O4 loading on the CNFs mat had shown a positive impact on improving the overall electrochemical performance of the assembled supercapacitors. A hybrid electrode loaded with NiCo2O4 twice as much as CNFs possess a specific capacitance value of 540 F g−1 along with an energy density of 30 Wh kg−1 at a power density of 515.6 W kg−1. In addition, the device showed excellent cycling stability and high capacitance retention against 6000 charge-discharge cycles at a charging current of 1.0 A g−1.


2019 ◽  
Vol 292 ◽  
pp. 121956 ◽  
Author(s):  
Ruiwen Wang ◽  
Da Liu ◽  
Mei Yan ◽  
Lu Zhang ◽  
Wen Chang ◽  
...  

NANO ◽  
2020 ◽  
Vol 15 (04) ◽  
pp. 2050043
Author(s):  
Huayu Zhou ◽  
Jingjing Wang ◽  
Qiong Yang ◽  
Menglei Chen ◽  
Changsheng Song ◽  
...  

We report a one-step electrochemical deposition technique to prepare three-dimensional (3D) Ag hierarchical micro/nanostructured film consisting of well-crystallized Ag nanosheets grown on an indium tin oxide (ITO) conductive substrate. The Ag hierarchical micro/nanostructures were fabricated in the mixed solution of AgNO3 and sodium citrate in a constant current system at room temperature. Through reduction of Ag[Formula: see text] electrodeposited on the surface of ITO substrate, nanoparticles were grown to form nanosheets which further combined into 3D sphere-like microstructures. The 3D Ag micro/nanostructures have many sharp edges and nanoscale gaps which can give rise to good Raman-enhanced effect. Due to localized surface plasmon resonance (LSPR) effects, these special Ag micro/nanostructures exhibited good Raman-enhanced performance. Using Rhodamine 6G (R6G) molecules as probe molecule, we studied the influence of excitation wavelength on Raman enhancement. The results showed that the 532[Formula: see text]nm excitation wavelength is the best to obtain the strongest Raman signal and to reduce the influence of other impurity peaks. Using the as-synthesized Ag hierarchical micro/nanostructures, we can detect the 10[Formula: see text][Formula: see text]mol/L R6G aqueous solution, exhibiting great Raman-enhanced effect.


Energies ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1940
Author(s):  
Muhammad Usman Naseer ◽  
Ants Kallaste ◽  
Bilal Asad ◽  
Toomas Vaimann ◽  
Anton Rassõlkin

This paper presents current research trends and prospects of utilizing additive manufacturing (AM) techniques to manufacture electrical machines. Modern-day machine applications require extraordinary performance parameters such as high power-density, integrated functionalities, improved thermal, mechanical & electromagnetic properties. AM offers a higher degree of design flexibility to achieve these performance parameters, which is impossible to realize through conventional manufacturing techniques. AM has a lot to offer in every aspect of machine fabrication, such that from size/weight reduction to the realization of complex geometric designs. However, some practical limitations of existing AM techniques restrict their utilization in large scale production industry. The introduction of three-dimensional asymmetry in machine design is an aspect that can be exploited most with the prevalent level of research in AM. In order to take one step further towards the enablement of large-scale production of AM-built electrical machines, this paper also discusses some machine types which can best utilize existing developments in the field of AM.


2021 ◽  
Vol 22 (7) ◽  
pp. 3391
Author(s):  
Sylwia Grabska-Zielińska ◽  
Alina Sionkowska ◽  
Ewa Olewnik-Kruszkowska ◽  
Katarzyna Reczyńska ◽  
Elżbieta Pamuła

The aim of this work was to compare physicochemical properties of three dimensional scaffolds based on silk fibroin, collagen and chitosan blends, cross-linked with dialdehyde starch (DAS) and dialdehyde chitosan (DAC). DAS was commercially available, while DAC was obtained by one-step synthesis. Structure and physicochemical properties of the materials were characterized using Fourier transfer infrared spectroscopy with attenuated total reflectance device (FTIR-ATR), swelling behavior and water content measurements, porosity and density observations, scanning electron microscopy imaging (SEM), mechanical properties evaluation and thermogravimetric analysis. Metabolic activity with AlamarBlue assay and live/dead fluorescence staining were performed to evaluate the cytocompatibility of the obtained materials with MG-63 osteoblast-like cells. The results showed that the properties of the scaffolds based on silk fibroin, collagen and chitosan can be modified by chemical cross-linking with DAS and DAC. It was found that DAS and DAC have different influence on the properties of biopolymeric scaffolds. Materials cross-linked with DAS were characterized by higher swelling ability (~4000% for DAS cross-linked materials; ~2500% for DAC cross-linked materials), they had lower density (Coll/CTS/30SF scaffold cross-linked with DAS: 21.8 ± 2.4 g/cm3; cross-linked with DAC: 14.6 ± 0.7 g/cm3) and lower mechanical properties (maximum deformation for DAC cross-linked scaffolds was about 69%; for DAS cross-linked scaffolds it was in the range of 12.67 ± 1.51% and 19.83 ± 1.30%) in comparison to materials cross-linked with DAC. Additionally, scaffolds cross-linked with DAS exhibited higher biocompatibility than those cross-linked with DAC. However, the obtained results showed that both types of scaffolds can provide the support required in regenerative medicine and tissue engineering. The scaffolds presented in the present work can be potentially used in bone tissue engineering to facilitate healing of small bone defects.


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