hydrophobic self cleaning coatings and their applications .pptx

self cleaning coating

1. Hydrophobic Self-Cleaning Coatings Husna Zaheer

2. Contents Introduction Synthesis Durability test Challenges faced in coating composition Application

3. Self-Cleaning Coatings Specialized surface treatments or materials that possess the ability to autonomously remove dirt, contaminants, and particles from their surface. D esigned to maintain the cleanliness and appearance of a surface R educe the need for manual cleaning and maintenance

4. Types Hydrophilic Hydrophobic

5. Hydrophobic self-cleaning coatings Coatings with dual functionality Hydrophobicity Photocatalytic activity

6. Why We Need Extensive exposure to air rain and pollution surfaces become dirty, discolored fractured affecting the Performance Esthetics

7. Application Architectural heritage Anti icing Anti biofouling Fabric and textiles

8. Routes of Synthesis

9. SiO 2 -TiO 2 -PDMS Composite coating Synthesized by sol gel method TEOS ( tetraethyl orthosilicate) TTIP ( titanium tetra isopropoxide ) PDMS (polydimethylsiloxane) Oxalic Acid

10. Continue… Hydrolysis and condensation of TEOS

11. Continue… Hydrolysis and condensation of TTIP

12. Continue… Copolymerization of TEOS TTIP and PDMS

13. Coating components Role of SiO 2 Hardness and Durability Surface Roughness Reinforcement Chemical Resistance Hydrophobicity Enhancement

14. Role of PDMS Enhance adhesion and durability Hydrophobicity Flexibility UV protection Reduce the cost of raw material

15. Role of TiO 2 Photocatalytic degradation of organic pollutants Alcohols, carboxylic acids Volatile organic compounds, phenol

16. Photocatalytic Degradation of Organic Compounds organic compounds are degraded to CO 2 and H 2 HC 2 O 4 − + •OH → OH− + •COOH + CO 2 •COOH + O 2 → •HO 2 + CO 2 •HO2 + •HO2→ H 2 O 2 + O 2

17. Durability Test Water contact angle measurement Abrasion resistance test Chemical resistance test UV exposure test Dust and dirt adhesion test Weathering test

18. Why These Method and Material Methods Materials The above-mentioned preparation processes are complex required equipment is demanding limits the large-scale preparation and application Fluorinated silane coatings are expensive pollute the environment The sol-gel method has been widely used simple operation easy control of reaction conditions

19. Challenges Faced in Coating Composition Effectiveness Over Time Surface Compatibility Maintenance and Reapplication Variability in Performance Environmental Friendly Cost

20. Protection of Architectural Heritage commonly used material in historical structures limestone marble o ther calcareous stones These surfaces are affected by environmental pollution acid rain organic pollutants

21. Environmental Effect Acid Rain Cause Acid dissolution HNO 3 + CaCO 3 → Ca(NO 3 ) 2 + CO 2 + H 2 O Surface erosion H 2 SO 4 + CaCO 3 → CaSO 4 + CO 2 + H 2 O Organic Pollutants Cause Surface staning Biological growth

22. Experiment Result Synthesized coating tested on Concrete Portland-limestone sandstone marble surface 1 year of outdoor exposure photocatalytic action of TiO 2 remained unaffected the photocatalytic action was lowered due to the elimination of nanoparticles from the facial layer Reduction of TiO 2 concentration was more in limestone than in concrete and sand stone

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