Functionalization of wood/plant-based natural cellulose fibers with nanomaterials: a review

TAPPI Journal ◽  
2018 ◽  
Vol 17 (02) ◽  
pp. 92-111 ◽  
Author(s):  
Charu Agarwal ◽  
Levente Csoka
Keyword(s):  
Noble Metals ◽  
Tin Dioxide ◽  
Carbon Nanomaterials ◽  
Point Of Care ◽  
Functional Materials ◽  
Cellulose Fibers ◽  
Sensing Applications ◽  
Natural Cellulose ◽  
Macro Scale ◽  
Disposable Device

Being the most abundant natural biopolymer on earth, cellulose has been vastly exploited in a range of applications, from writing paper to high-end biosensors. Natural cellulose fibers can be isolated from wood or non-woody plants such as hemp, jute, flax, and bamboo by chemical or mechanical treatments. To make it suitable for targeted applications, cellulose fibers are modified with functional moieties in the nanometer scale. Cellulose has been functionalized with noble metals such as silver and gold nanoparticles for catalysis and antimicrobial applications. A number of metal oxides, such as zinc oxide, titanium dioxide, and tin dioxide have been incorporated into cellulose. The porosity, hydrophilicity, and roughness of cellulose surface makes it an ideal substrate for a plethora of sensing applications. Further, it can be made into a lightweight, portable, foldable, and disposable device, which provides an excellent platform for various point-of-care purposes. Cellulose fibers have also been immobilized with carbon nanomaterials, including carbon nanotubes and graphene oxide. For optical applications, [Fe(hptrz)3](OTs)2 spin-crossover nanoparticles have also been immobilized on cellulose fibers. Likewise, many enzymes, macromolecules, and some polymers have been used to modify natural cellulose for specific end uses. This review focuses on recent developments in the modification or immobilization of functional materials on cellulose fibers, in macro-scale only, obtained from wood or plant sources.

Metallic and Semiconducting Nanowires from Single Wall Carbon Nanotubes

2004 ◽  
Vol 818 ◽  
Author(s):  
Kousik Sivakumar ◽  
Shaoxin Lu ◽  
Balaji Panchapakesan
Keyword(s):  
Carbon Nanotubes ◽  
Silver Nanowires ◽  
Functional Materials ◽  
Nano Particles ◽  
Single Wall Carbon Nanotubes ◽  
Structure Property ◽  
Semiconducting Nanowires ◽  
Sensing Applications ◽  
Macro Scale ◽  
Different Types

AbstractThe focus of today's research has largely shifted from macro scale to micro scale and further to nano scale. The reason being the desire to realize quantum size effects in devices that has long eluded scientists around the world alike. With the discovery of nanoparticles, nanowires, and nanotubes, the ability to realize these effects practically into devices has increased manifold. Integration of carbon nanotubes with different types of functional materials may become mandatory in the future for electronics and sensing applications and in this sense, nucleation, growth and evolution of the structure of metallic and semiconducting materials on carbon nanotubes may be necessary. Further, it also provides opportunities to do fundamental research on understanding the structure-property relationships of these nanowires using carbon nanotubes. In this paper, we present a technique to form metallic and semiconducting nanowires using carbon nanotubes themselves as templates. Nanowires of silver and platinum have been fabricated by the electric field assisted deposition of nano particles of these metals on single walled carbon nanotubes. SEM and TEM investigations have shown the dimensions of the nanowires to be dependent only on the size of the nanoparticles, 10 - 100 nm in our case. The silver nanowires exhibited linear current – voltage characteristics whereas the platinum nanowires exhibited non-linear characteristics beyond a certain bias. This technique provides a high degree of selectivity by manipulating the charges on the surface of the nanotubes, which enables the deposition of metals only on the nanotubes and not anywhere else. The versatility of this technique allows for the fabrication of different types of metallic and semiconducting nanowires at the same dimensions as carbon nanotubes.

Well-defined polyindole–Au NPs nanobrush as a platform for electrochemical oxidation of ethanol

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Magdalena Warczak ◽  
Marianna Gniadek ◽  
Kamil Hermanowski ◽  
Magdalena Osial
Keyword(s):  
Conducting Polymers ◽  
Hybrid Material ◽  
Noble Metals ◽  
Electrochemical Impedance ◽  
Electrochemical Sensing ◽  
Alkaline Media ◽  
X Ray Diffraction ◽  
Long Term Stability ◽  
Sensing Applications ◽  
Energy Conversion Devices

Abstract Over the recent decades, conducting polymers have received great interest in many fields including microelectronics, energy conversion devices, and biosensing due to their unique properties like electrical conductivity, stability, and simple synthesis. Modification of conducting polymers with noble metals e.g. gold enhances their properties and opens new opportunities to also apply them in other fields like electrocatalysis. Here, we focus on the synthesis of hybrid material based on polyindole (PIN) nanobrush modified with gold nanoparticles and its application towards electrooxidation of ethanol. The paper presents systematic studies from synthesis to electrochemical sensing applications. For the characterization of PIN–Au composites, scanning electron microscopy and X-ray diffraction analyses were used. The electrocatalytic performance of the proposed hybrid material towards alcohol oxidation was studied in alkaline media by cyclic voltammetry, chronoamperometry, and electrochemical impedance spectroscopy techniques. The results show that PIN–Au hybrid can be employed as an effective and sensitive platform for the detection of alcohols, which makes it a promising material in electrocatalysis or sensors. Moreover, the proposed composite exhibits electrocatalytic activity towards ethanol oxidation, which combined with its good long-term stability opens the opportunity for its application in fuel cells.

scholarly journals Shape-Memory Nitinol Tympanostomy Tube and All-in-One Introducer Device for Treatment of Otitis Media

2010 ◽  
Vol 4 (2) ◽  
Author(s):  
Michael Loushin ◽  
Keith Leland
Keyword(s):  
Shape Memory ◽  
Otitis Media ◽  
Point Of Care ◽  
The United States ◽  
Tube Placement ◽  
Tympanostomy Tube ◽  
Office Visits ◽  
Antibiotic Resistant ◽  
Bacterial Organism ◽  
Disposable Device

Otitis media is the most common bacterial illness in children, resulting in millions of office visits, antibiotic prescriptions, and surgical procedures annually in the United States. Antibiotics are commonly prescribed and has resulted in increased prevalence of antibiotic resistant strains of organisms. Additionally, patients with otitis media are candidates for tympanocentesis, myringotomy, and tympanostomy tube placement procedures. The ability to safely and efficiently perform these procedures to accurately diagnose, identify the bacterial organism, and treat otitis media with point of care therapy is needed. A shape-memory nitinol tympanostomy tube and an all-in-one introducer device (OtoStent tympanostomy device) currently under development will allow clinicians to safely and efficiently perform myringotomy, tympanocentesis, and tympanostomy tube placement with a single disposable device.

scholarly journals Crystal Structure, Lattice Strain, Morphology, and Electrical Properties of SnO2 Nanoparticles Induced by Low Calcination Temperature

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Panya Khaenamkaew ◽  
Dhonluck Manop ◽  
Chaileok Tanghengjaroen ◽  
Worasit Palakawong Na Ayuthaya
Keyword(s):  
Thin Films ◽  
Electrical Properties ◽  
Calcination Temperature ◽  
Tin Dioxide ◽  
Lattice Strain ◽  
Dielectric Constants ◽  
Precipitation Method ◽  
Calcination Temperatures ◽  
Sensing Applications ◽  
Crystallite Sizes

The electrical properties of tin dioxide (SnO2) nanoparticles induced by low calcination temperature were systematically investigated for gas sensing applications. The precipitation method was used to prepare SnO2 powders, while the sol-gel method was adopted to prepare SnO2 thin films at different calcination temperatures. The characterization was done by X-ray diffraction, scanning electron microscopy (SEM), and atomic force microscopy (AFM). The samples were perfectly matched with the rutile tetragonal structure. The average crystallite sizes of SnO2 powders were 45 ± 2, 50 ± 2, 62 ± 2, and 65 ± 2 nm at calcination temperatures of 300, 350, 400, and 450°C, respectively. SEM images and AFM topographies showed an increase in particle size and roughness with the rise in calcination temperature. The dielectric constant decreased with the increase in the frequency of the applied signals but increased on increasing calcination temperature. By using the UV-Vis spectrum, the direct energy bandgaps of SnO2 thin films were found as 4.85, 4.80, 4.75, and 4.10 eV for 300, 350, 400, and 450°C, respectively. Low calcination temperature as 300°C allows smaller crystallite sizes and lower dielectric constants but increases the surface roughness of SnO2, while lattice strain remains independent. Thus, low calcination temperatures of SnO2 are promising for electronic devices like gas sensors.

scholarly journals Numerical analysis of an infrared gas sensor utilizing an indium-tin-oxide-based plasmonic slot waveguide

2022 ◽  
Vol 11 (1) ◽  
pp. 15-20
Author(s):  
Parviz Saeidi ◽  
Bernhard Jakoby ◽  
Gerald Pühringer ◽  
Andreas Tortschanoff ◽  
Gerald Stocker ◽  
...  
Keyword(s):  
Tin Oxide ◽  
Indium Tin Oxide ◽  
Noble Metals ◽  
Microelectromechanical Systems ◽  
Propagation Loss ◽  
Slot Waveguide ◽  
Plasmonic Waveguides ◽  
Propagation Length ◽  
Plasmonic Material ◽  
Sensing Applications

Abstract. Plasmonic waveguides have attracted much attention owing to the associated high field intensity at the metal–dielectric interface and their ability to confine the modes at the nanometer scale. At the same time, they suffer from relatively high propagation loss, which is due to the presence of metal. Several alternative materials have been introduced to replace noble metals, such as transparent conductive oxides (TCOs). A particularly popular TCO is indium tin oxide (ITO), which is compatible with standard microelectromechanical systems (MEMS) technology. In this work, the feasibility of ITO as an alternative plasmonic material is investigated for infrared absorption sensing applications: we numerically design and optimize an ITO-based plasmonic slot waveguide for a wavelength of 4.26 µm, which is the absorption line of CO2. Our optimization is based on a figure of merit (FOM), which is defined as the confinement factor divided by the imaginary part of the effective mode index (i.e., the intrinsic damping of the mode). The obtained optimal FOM is 3.2, which corresponds to 9 µm and 49 % for the propagation length (characterizing the intrinsic damping) and the confinement factor, respectively.

Nano-functionalized Paper-based IoT enabled Devices for Point-of-Care Testing: A Review

2021 ◽  
Author(s):  
Vinay Kishnani ◽  
Ankur Gupta
Keyword(s):  
Point Of Care ◽  
Research Work ◽  
Functional Materials ◽  
Point Of Care Testing ◽  
Environment Friendly ◽  
Iot Platform ◽  
Art Research ◽  
Detection Mechanisms ◽  
The Internet Of Things ◽  
Sensing Characteristics

Over the last few years, the microfluidics phenomenon coupled with the Internet of Things (IoT) using innovative nano-functional materials have been recognized as one of the sustainable and economical tools for point of care testing (POCT) of various pathogens influencing the human health. The sensors based on these phenomena are aimed to be designed for their cost-effectiveness, to make it handy, environment-friendly and to get an accurate, easy, and rapid response. Considering the burgeoning importance of analytical devices in the healthcare domain, this review paper is based on the gist of sensing aspects of the micro fabricated paper-based analytical devices (μPADs). The article discusses not only the various used design methodologies and fabrication approaches, but also elucidates the recently reported surface modification strategies, detection mechanisms viz., colorimetric, electrochemical, fluorescence, electrochemiluminescence etc., and sensing characteristics of μPADs along with reported works equipped with the IoT platform for digital readout. In a nutshell, this article summarizes the state-of-the-art research work carried out over the nano functionalized paper-based analytical devices and associated challenges/solutions in the point of care testing domain.

Extraction and characterisation of natural cellulose fibers from Kigelia africana

2020 ◽  
Vol 236 ◽  
pp. 115996 ◽  
Author(s):  
Manikandan Ilangovan ◽  
Vijaykumar Guna ◽  
B. Prajwal ◽  
Qiuran Jiang ◽  
Narendra Reddy
Keyword(s):  
Cellulose Fibers ◽  
Natural Cellulose
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