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

2

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

3

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.

4

Growth of Nano Rods

5

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

6

Homogeneous Nucleation Heterogeneous NucleationNucleation takes place within nucleating

materialNucleation takes place on some external

materials

Nucleation

7

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

8

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

9

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)

10

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

11

Seedless growth of Nano RodsSEM image of Nano rods grown Cotton modified with

Methyltrimethoxysilane

12

Flower like structures grew on scattered with nano rods as their petals

Seedless growth of Nano Rods� Fluorinated polymer (Unidyne)

13

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

14

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

17

Seedless growth of Nano Rods� Atomic Force Microscopy

18

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

19

Seeded Growth� A layer of nano seeds is deposited on susbtrate

� Nano rods are grown on these seeds

20

Seeded Growth on PET Fabric

21

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

22

Charaterization of Nano rods with SEM

Nano rods grew uniformly on seeded PET Fabric

Seeded Growth

23

Lotus Effect� Lotus effect is cleaning of a surface when water

droplet rolls over it

• Surface roughness• Superhydrophobicity θ>150°

Lotus Effect� Superhydrophobicity

25

Modification with Octadecyltrimethoxysilane

Solution method Chemical vapor deposition

ODS

At 40°CFor 24 Hours

ODS

Sample

At 150°C for 2 Hours

Lotus Effect

26

Characterization of Lotus Effect

1. Water Contact Angle

2. Water Sliding Angle

Water Contact Angle

Water Sliding Angle

α

Superhydrophobicity� Characterization of Superhydrophobicity

27

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