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Munir ASHRAFa, Anne PERWUELZ a,Christine CAMPAGNEa,
Philippe CHAMPAGNEb, Christian Courtoisb, Anne LERICHEb
aLABORATOIRE DE GENIE MATERIAUX ET TEXTILES ROUBAIXbLABORATOIRE DES MATERIAUX CERAMIQUES ET PROCEDES ASSOCIES
1Congrès de la Société Belge de Céramique 7 Février 2011
Objectives� Development of Multifunctional Textile
• Lotus Effect
• UV absorption
• Photocatalytic Effect
� Growth of ZnO nano rods on textiles by using hydrothermal process
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Plan of Presentation� Introduction� Growth of nano rods
• Seedless growth• Seeded growth• Characterization of nano rods
� Study of functional properties of textiles• Lotus Effect• UV absorption• Antibacterial properties
� Conclusion
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Introduction � A textile which has one of the following charateristics
like antibacterial, moisture management, flame-retardancy , antistatic effect, water repellancy, and so on, is called functional textile.
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Growth of Nano Rods
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Seedless Seeded
Growth of Nano Rods� 1st step in seedless growth is nucleation
� Formation of nuclei from zinc oxide precursor solution
� Nucleation is of two types
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Homogeneous Nucleation Heterogeneous NucleationNucleation takes place within nucleating
materialNucleation takes place on some external
materials
Nucleation
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r*
Substrate
r*
Homogeneous Nucleation Heterogeneous Nucleation
r*= critical radius of nucleus
Nucleation� Minimum energy required for nucleation is called Nucleation Energy Barrier
� NEB for heterogeneous nulceation is much
less than homogeneous nucleation
Homogeneous Nucleation
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Energy released due to formation of volume
Energy comsumed due to formation of interface
Heterogeneous NucleationΔG= Nucleation Energy BarrierGv = volume energyr= radius of nucleus
б= surface free energy
Nucleation� Two Extreme Cases
Example of heterogeneous nucleation
Bubbles of carbon dioxide nucleating on
thumb
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Seedless growth of Nano Rods on Cotton
� For nucleation on substrate 0<θ<180
� Modification of cotton fabric with hydrophobic chemicals
• Methyltrimethoxysilane
• Fluorinated polymer (Unidyne)
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Application to Textiles
Seedless growth of Nano RodsProcedure for growth of nano rods
Zinc nitrate hexahydrate
Hexamethylenetetramine
Conditions
Temperature 90°C
Time 2 hours
Reactions
(CH2)6 N4 + 6H2O 6HCHO + 4NH3
NH3 + H2O NH4⁺ + OH⁻
2OH + Zn⁺ ⁺ Zn(OH)2
Zn(OH)2 ZnO + H2O
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Seedless growth of Nano RodsSEM image of Nano rods grown Cotton modified with
Methyltrimethoxysilane
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Flower like structures grew on scattered with nano rods as their petals
Seedless growth of Nano Rods� Fluorinated polymer (Unidyne)
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Nano rods grew on scattered places
Seedless growth of Nano Rods� As nano rods grew on scattered places on modified cotton fabric.
� The possible reason is the nonuniformity of surfaces
� PET film was chosen as susbtrate for nano rods growth
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PET Film
Plasma treatment
Chemical Vapor deposition
Growth of Nano rods
Growth of Nano rods
Growth of Nano rods(Octadecyltrimethoxysilane)
Seedless growth of Nano Rods� Growth on un treated PET Film
15Nano Rods grew as Petals of flowers
Seedless growth of Nano Rods� Growth of nano rods on Plasma treated PET Film
16No Nano rods grew on Plasma treated Film
Seedless growth of Nano Rods� Growth of nano rods on PET film modified with CVD
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Seedless growth of Nano Rods� Atomic Force Microscopy
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Conclusion and Perspective � Untreated PET Film----> No growth----> surface is too hydrophobic
� Plasma treated PET film---> No growth----> surface is too hydrophilic
� Plasma treated PET Film Modified with CVD---> Growth of Nano Rods
� Presence of both hydrophobic and hydrophilic groups is necessary for growth
� Working to grow Nano rods on cotton and PET fabric using these conditions
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Seeded Growth� A layer of nano seeds is deposited on susbtrate
� Nano rods are grown on these seeds
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Seeded Growth on PET Fabric
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Polyester Fabric Plasma Treatment Seeding Growth of Nano Rods
Characterization of Nano Rods
SEM AFM
Study of Functional Properties
Photocatalytic propertiesUV AbsorptionLotus Effect
Seeded Growth on PET Fabric
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Charaterization of Nano rods with SEM
Nano rods grew uniformly on seeded PET Fabric
Seeded Growth
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Lotus Effect� Lotus effect is cleaning of a surface when water
droplet rolls over it
• Surface roughness• Superhydrophobicity θ>150°
Lotus Effect� Superhydrophobicity
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Modification with Octadecyltrimethoxysilane
Solution method Chemical vapor deposition
ODS
At 40°CFor 24 Hours
ODS
Sample
At 150°C for 2 Hours
Lotus Effect
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Characterization of Lotus Effect
1. Water Contact Angle
2. Water Sliding Angle
Water Contact Angle
Water Sliding Angle
α
Superhydrophobicity� Characterization of Superhydrophobicity
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Water Contact angle Water Sliding Angle
Solution Modification Chemical vapor deposition
153°±3° 158°±2°
Solution Modification Chemical vapor deposition
α
Sliding angle= 3°-4° Sliding angle= 1-2°
Conclusion� We successfully grew the Nano Rods on PET Fabric
with uniform surface roughness
� Very small water sliding angle was obtained which implies minimum Contact Angle hystersis
� We obtained LOTUS EFFECT
� Working to improve water contact angle
� Working to study the UV absorption and other Photocatalytic related Properties