nanotechnologies coatings
TRANSCRIPT
-
7/30/2019 Nanotechnologies Coatings
1/23
Nanotechnologies for
Textiles, Clothing andFootwear
Dr. Jimmy LamInstitute of Textiles & Clothing
-
7/30/2019 Nanotechnologies Coatings
2/23
Agenda Introduction Applications
Nano-fibres Nano-composite fibres Carbon nano-tubes Nano-coated fibres
Future Prospects
-
7/30/2019 Nanotechnologies Coatings
3/23
Introduction Nano is derived from the Greek word,nanos, meaning dwarf, and in SI units,the prefix nano is used as a factorindicating 10-9.
One nanometer (nm) is 0.000000001m By comparison, the diameter of single
human hair is 80,000nm, and human redblood cell is 7000nm wide and a watermolecule is almost 0.3nm.
-
7/30/2019 Nanotechnologies Coatings
4/23
Nano-science and
nano-technology Both nano-science and nano-technology are
concerned with materials that are very small.
Nano-scale has generally been taken to liefrom 0.2nm (atom) to 100nm.
Nano-science is defined as the study ofphenomena and manipulation of materials at
atomic, molecular and macro-molecularscales, where the properties of materialsdiffer markedly from those at larger scale.
-
7/30/2019 Nanotechnologies Coatings
5/23
Nano-science and
nano-technology2 Nano-technologies, on the other hand, refer
to the design, characterisation, production
and application of structures, devices andsystems, by controlling shape and size at thenano-metre scale.
Nano-technologies may be considered as a
range of methods of manufacturing materialsalong the lines of atomic assembly.
-
7/30/2019 Nanotechnologies Coatings
6/23
Nano-science and
nano-technology3 Atoms, molecules and nano-sized
materials are thereby manipulated in a
thorough, precise and controlledmanner to produce novel materials withinnovative and different properties to
those obtained by conventional materialengineering at the micro-scale.
-
7/30/2019 Nanotechnologies Coatings
7/23
Nano-science and
nano-technology4 Nano-technology has been termed a bottom-up technology because of the use of suchsmall scale building units.
Conventional materials engineering at themacro-scale is, by contrast, considered as atop-down approach.
The use of nano-science and nano-technology
to control the internal structure of amaterial at nano-scale is considered to leadto materials with fewer defects and henceof a higher quality.
-
7/30/2019 Nanotechnologies Coatings
8/23
Application of nano-technogies for textile
-
7/30/2019 Nanotechnologies Coatings
9/23
Three approaches1. For nano-materials that are nano-scale inone dimesion, application of very thinsurface coating (2nm-100nm) to textile
materials.2. Nano-fibres and nanotubes are esentiallynano-scale in two dimensions and theirutilization in many forms of compositematerials offers opportunities for improve
the mechanical properties, alteringelectrical, optical or biologicalcharacteristics.
-
7/30/2019 Nanotechnologies Coatings
10/23
Three approaches3. The third approach involves the useof nano-particles (nano-scale in three
dimensions) for incorporation infibres, coating, films to provide amyriad of possibilities such asimparting antimicrobial, flameretardant and chemical softeningeffects to textiles and clothing.
-
7/30/2019 Nanotechnologies Coatings
11/23
Example 1:
nanofibres Nano-fibres are generally taken to be fibres with adiameter less than 1m (100nm).
Electrospinning is the major fibre production
method used to make nano-fibres. In this method a polymer fluid (melt or soloution) ischarged with a high electrical voltage and extrudedthrough a spinneret of 0.1-1nm in diameter, theextruded polymer jet being drawn towards an
earthered collector. By manipulation of the electro-spinning conditions,
micro-filaments can be produced with differentdiameters.
-
7/30/2019 Nanotechnologies Coatings
12/23
Electro-spinning
Nano-fibres
-
7/30/2019 Nanotechnologies Coatings
13/23
Example1:
nanofibres 2 Nano-fibres produced from syntheticfibre materials can be formed with ahigh surface area to volume ratio andsmall pores sizes in fabric form.
The potential end uses for such nano-fibres are in filtration, wound
dressings, tissue engineering, nano-composites, drug delivery devices andsensors.
-
7/30/2019 Nanotechnologies Coatings
14/23
Example2:
nano-composites fibres Nano-composite fibres consist of nano-fibres containing particles with onedimension in the nano-metre range.
The particles may be spheres, fibrils and byvarying the amounts, their alignment, anddistribution within the nano-fibre
improvements in the mechanical, electrical,optical or biological properties may beobtained.
-
7/30/2019 Nanotechnologies Coatings
15/23
Nano-composite fibres
-
7/30/2019 Nanotechnologies Coatings
16/23
Example3:
Carbon nano-tubes The carbon nano-tubes essentially consistof tiny shells of graphite rolled up intocylinders, either as single tubes or multiple
tubes joined together. The carbon nano-tubes exhibit remarkableproperties: a tensile strength some one hundred times that
of steel at one sixth of the weight.
A thermal conductivity superior to all but thepurest diamond;
Electrical conductivity similar to copper but withan ability to carry much higher electricalcurrents.
-
7/30/2019 Nanotechnologies Coatings
17/23
Carbon Nano-tubes
-
7/30/2019 Nanotechnologies Coatings
18/23
Example4:
Nano-coated fibres Nano-coating the surfaces of textiles,clothing and textiles for footwear is oneapproach to the production of highly
effective anti-microbial treatments forkilling the bacteria that can lead tomalodour formation. electrical currents.
The nano-coating is held on the fibresurface by strong electrostatic and
hydrogen bonds and punctures the bacterialwall, killing bacteria that can accumulate intextiles and clothing through the retentionof human respiration exuded throughphysical activity and wear.
-
7/30/2019 Nanotechnologies Coatings
19/23
Example4:
Nano-coated fibres2 Nano-coating of textile fabrics,complete finished garments or shoes
can be obtained by plasma polymertreatment.
Plasma is the fourth state of matter
(after solid, liquids and gases) whichwas proposed by Sir William Crookers,as a result of experiments in thepassage of electricity through gases.
-
7/30/2019 Nanotechnologies Coatings
20/23
Nano-coating
Plasma Treatment
-
7/30/2019 Nanotechnologies Coatings
21/23
Example4:
Nano-coated fibres3 A plasma generated by electrical dischargethrough gas consists of a mixture ofpositive and negative ions, electrons, free
readicals, ultraviolet radiation, and manydifferent electronically excited molecules. By vary the conditions of the plasma
treatment and the nature of the specificgas presents, a variety of surface
treatments can be produced that changethe chemical or physical nature of the fibresurface, thereby radically altering alltreatments that depend upon fibreadhesion, eg coating, lamination and bonding.
-
7/30/2019 Nanotechnologies Coatings
22/23
Future prospects
The main trust in nano-technologies applied totextiles, clothing and footwear will be to: Improve the properties and performance of existing
materials;
Develop smart and intelligent textiles with novelfunctions;
Greatly increase the use of fibres in technical textiles,biomedical and healthcare options; and
Open up new opportunities for fibres as sensors.
Overall, nano-technologies offer great potentialfor the future and could radically changeconsumer perception of what constitutes astandard apparel fabric.
-
7/30/2019 Nanotechnologies Coatings
23/23
References Nano-technologies for Textile,Clothing, and Footwear by Ian Holme,
Textile Magazine 2005, Vol.32, No. 1,p.7.