scholarly journals Lessons from nature for green science and technology: an overview and bioinspired superliquiphobic/philic surfaces

2018 ◽  
Vol 377 (2138) ◽  
pp. 20180274 ◽  
Author(s):  
Bharat Bhushan
Keyword(s):  
Human Impact ◽  
Science And Technology ◽  
Theme Issue ◽  
Biologically Inspired ◽  
Aquatic Animals ◽  
Structured Surfaces ◽  
Commercial Interest ◽  
General Field ◽  
Commercial Applications

Nature has developed materials, objects and processes that function from the macroscale to the nanoscale. The emerging field of biomimetics allows one to mimic biology or nature to develop nanomaterials, nanodevices and processes which provide desirable properties. The biologically inspired materials and structured surfaces are being explored for various commercial applications. These should have minimum human impact on the environment, leading to eco-friendly or green science and technology. There are a large number of flora and fauna including bacteria, plants, land and aquatic animals, and seashells with properties of commercial interest. The paper presents an overview of the general field of biomimetics followed by a detailed overview of mechanisms, fabrication techniques and characterization of superliquiphobic/philic surfaces and their applications.This article is part of the theme issue ‘Bioinspired materials and surfaces for green science and technology’.

scholarly journals Development and Characterization of Teflon-Copper Composite Material

2018 ◽  
Vol 778 ◽  
pp. 225-229
Author(s):  
Imran Hamid ◽  
Abdul Rauf ◽  
Faisal Nasim ◽  
Muhammad Siddique ◽  
Adnan Gul
Keyword(s):  
Composite Material ◽  
Hot Isostatic Pressing ◽  
Solid Lubricants ◽  
Powder Metallurgy Technique ◽  
Covalent Bonds ◽  
Secondary Bonds ◽  
Three Samples ◽  
Commercial Applications ◽  
Copper Composite

Composites are the combination of materials that are mixed together to achieve specific structural properties. Teflon (Polytetrafluoroethylene PTFE) consists of long-chain molecular structure. Its monomer consists of two carbon atoms each of them having flourine atoms attached. Bonds within each chain are strong covalent bonds where as the secondary bonds between two chains are weaker. By raising temperature, the distance between the chains increases providing good adjustment of the atoms of other materials due to anisotropy of its mechanical properties. Powder metallurgy technique using hot isostatic pressing, a hybrid densification process in which pressure and temperature are applied at the same time, has been used to develop a teflon-copper composite material. Three samples were prepared by changing the teflon-copper composition as 60:40%, 65:35% and 70:30% by weight. Commercially available powders of teflon and copper of grain size ~ 40 μm was used. The aim to develop this type of material was to increase its density (~ 4 g/cm3), and hardness. The commercial applications of such type of composite material are solid lubricants, sleeves, bearings etc. In this paper the effect of composition on hardness, tensile strength and surface roughness is studied.

Molecular methods for the detection and characterization of foodborne pathogens

2010 ◽  
Vol 82 (1) ◽  
pp. 69-79 ◽  
Author(s):  
Xian-Ming Shi ◽  
Fei Long ◽  
Biao Suo
Keyword(s):  
Foodborne Pathogens ◽  
Biochemical Characterization ◽  
Molecular Methods ◽  
Nucleic Acid Hybridization ◽  
Food Industries ◽  
Restriction Length Polymorphism ◽  
Polymerase Chain ◽  
Commercial Applications ◽  
Restriction Length

The surveillance of foodborne pathogens in food industries has shown the urgent need for rapid and dependable methods to detect and characterize the organisms in food and environments of clinical and epidemiologic importance. Recent studies on rapid methods in microbiology have been focused on biochemical characterization, immunoassays, and molecular methods. Many molecular methods have been developed and applied to the detection and characterization of foodborne pathogens in laboratories and food industries. They can be mainly divided into DNA banding pattern-based tests and DNA sequence-based tests. The former includes nucleic acid hybridization, polymerase chain reaction (PCR), amplified restriction length polymorphism, and randomly amplified polymorphic DNA, etc. Most of these methods in commercial applications are based on PCR or hybridization techniques. The principle, characteristics, and application of molecular methods for the detection and characterization of foodborne pathogens were reviewed in this article.

scholarly journals Characterization of polyvinyl alcohol-borax/agarose (PVA-B/AG) double network hydrogel utilized for the cleaning of works of art

2020 ◽  
Author(s):  
Ehab Awad Al-Emam ◽  
Hilde Soenen ◽  
Joost Caen ◽  
Koen Janssens
Keyword(s):  
Polyvinyl Alcohol ◽  
Self Healing ◽  
Retention Capacity ◽  
Structured Surfaces ◽  
Double Network ◽  
Liquid Retention ◽  
Long Time ◽  
Cleaning Procedures ◽  
Phase Retention

Abstract Since cleaning of artworks may cause undesirable physicochemical alterations and is a nonreversible procedure, it is mandatory to adopt the proper cleaning procedure. Such a procedure should remove undesired materials whilst preserving the original surface. In this regard, numerous gels have been developed and exploited for the cleaning of various artwork surfaces. Lately, agarose (AG) and polyvinyl alcohol-borax (PVA-B) hydrogels have been widely employed as cleaning tools by conservators. Both hydrogels show some limitations in specific cleaning practices. In this work, we investigated the influence of including increased levels of agarose into PVA-B systems. For this reason, we performed a detailed characterization on the double network (DN) hydrogel including the chemical structure, the liquid phase retention, the rheological behavior, and the self-healing behavior of various PVA-B/AG double network hydrogels. These new hydrogels revealed better properties than PVA-B hydrogels and obviated their limitations. The inclusion of AG into PVA-B systems enhanced the liquid retention capacity, shape-stability, and mechanical strength of the blend. Furthermore, AG minimized the expelling/syneresis issue that occurs when loading PVA-B systems with low polarity solvents or chelating agents. The resultant double network hydrogel exhibits relevant self-healing properties. The PVA-B/AG double network is a new and useful cleaning tool that can be added to the conservators’ tool-kit. It is ideal for cleaning procedures dealing with porous and complex structured surfaces, vertical surfaces and for long time applications.

scholarly journals Stability Evaluation and Degradation Studies of DAC® Hyaluronic-Polylactide Based Hydrogel by DOSY NMR Spectroscopy

Biomolecules ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1478
Author(s):  
Tatiana Guzzo ◽  
Fabio Barile ◽  
Cecilia Marras ◽  
Davide Bellini ◽  
Walter Mandaliti ◽  
...  
Keyword(s):  
Hyaluronic Acid ◽  
Nmr Spectroscopy ◽  
Bone Growth ◽  
Orthopedic Implants ◽  
Structured Surfaces ◽  
Physiological Conditions ◽  
Hydrophilic Character ◽  
Dosy Nmr ◽  
The Stability

The stability and the degradation of polymers in physiological conditions are very important issues in biomedical applications. The copolymer of hyaluronic acid and poly-D,L-lactic acid (made available in a product called DAC®) produces a hydrogel which retains the hydrophobic character of the poly-D,L-lactide sidechains and the hydrophilic character of a hyaluronic acid backbone. This hydrogel is a suitable device for the coating of orthopedic implants with structured surfaces. In fact, this gel creates a temporary barrier to bacterial adhesion by inhibiting colonization, thus preventing the formation of the biofilm and the onset of an infection. Reabsorbed in about 72 h after the implant, this hydrogel does not hinder bone growth processes. In the need to assess stability and degradation of both the hyaluronan backbone and of the polylactic chains along time and temperature, we identified NMR spectroscopy as a privileged technique for the characterization of the released species, and we applied diffusion-ordered NMR spectroscopy (DOSY-NMR) for the investigation of molecular weight dispersion. Our diffusion studies of DAC® in physiological conditions provided a full understanding of the product degradation by overcoming the limitations observed in applying classical chromatography approaches by gel permeation UV.

Development and Comfort Characterization of 2D-Woven Auxetic Fabric for Wearable and Medical Textile Applications

2018 ◽  
Vol 36 (3) ◽  
pp. 199-214 ◽  
Author(s):  
Mumtaz Ali ◽  
Muhammad Zeeshan ◽  
Sheraz Ahmed ◽  
Bilal Qadir ◽  
Yasir Nawab ◽  
...  
Keyword(s):  
Air Permeability ◽  
Woven Fabric ◽  
Medical Applications ◽  
Simple Method ◽  
Fabric Structure ◽  
Medical Textile ◽  
Commercial Applications ◽  
Auxetic Structure ◽  
Higher Sensitivity

Knitted auxetic fabrics (AF) are in common practice but their stability and thickness are major problems in commercial applications. Therefore, a simple method of developing woven AF is proposed here. Differential shrinking property of different weaves is utilized to visualize auxetic honey comb geometry in fabric structure. Based on this fabric structure, auxeticity is induced in 2-D-woven fabric. AF is developed using conventional nonauxetic materials (i.e., cotton in warp and elastane [Lycra] yarn in the weft). Auxetic nature and auxetic structure in the fabric were characterized by microscope. Comfort properties (air permeability, thermal resistance, stiffness, and wicking) of AF were compared with conventional nonauxetic fabrics (NAF). Piezoresistive nature of conductive AF and NAF is also compared. AF showed superior comfort properties and higher sensitivity as compared to conventional NAF. Based on results, AF can be considered better replacement of conventional NAF in wearable and medical applications.

scholarly journals Bioinspired triangular patterns for water collection from fog

2019 ◽  
Vol 377 (2150) ◽  
pp. 20190128 ◽  
Author(s):  
Dong Song ◽  
Bharat Bhushan
Keyword(s):  
Pressure Gradient ◽  
Science And Technology ◽  
Laplace Pressure ◽  
Theme Issue ◽  
Droplet Motion ◽  
Triangular Shape ◽  
Conical Shape ◽  
Bioinspired Materials ◽  
Water Collection ◽  
Curvature Gradient

Cacti use spines with conical geometry to transport water to its base. A conical shape with curvature gradient generates a Laplace pressure gradient along the droplet, which is responsible for droplet motion. In this study, the triangular shape was used which also generates a Laplace pressure gradient along the droplet. A bioinspired surface, composed of a hydrophilic triangular pattern surrounded by a rim of superhydrophobic region, was used to transport water collected from the fog on the hydrophilic pattern. The growing droplets start to coalesce into bigger ones. Eventually, they are big enough to touch the superhydrophobic borders, which trigger the transport motion. Droplet mobility and water collection measurements were made on triangular patterns with various geometries to determine the most efficient configurations. Results from this study can be used to enhance the performance of water collection systems from fog. This article is part of the theme issue ‘Bioinspired materials and surfaces for green science and technology (part 2)’.

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