This document discusses strategies for creating antifogging coatings. It begins by introducing the problem of fogging on surfaces and its negative effects. It then covers fundamental aspects like surface tension and wettability. The rest of the document discusses different strategies for creating antifogging coatings, including superhydrophilic, superhydrophobic, and hygroscopic coatings. It also covers common materials used for polymer and inorganic antifogging coatings and concludes by discussing the advantages and disadvantages of different approaches.

1. HOW TO MAKE SURFACE ANTIFOGGING
MM 650 : PROTECTIVE COATINGS
PRESENTATION
Presented by
Neha Choudhary
(22M1876)

2. 1. Introduction
2. Fundamental Aspects
3. Strategies to Antifogging Property
4. Material of antifogging coatings
5. Practical Applications
6. Conclusion
7. References
OUTLINE

3. INTRODUCTION
• Fogging of transparent surface is the condensation of water-vapor in the air into small discrete
liquid drops on the surface as a result of the temperature difference between the surface and
humid environment causing scatters of incident light and create a blurry vision.
• Fog forms on the common solid substrates, such as eyeglasses, mirrors, goggles and films like
fresh food bags, to name a few.
• Fogging is influenced by several factors which are
temperature, humidity level, and airflow.

4. Approaches to solve
the problem
of antifogging
Issues due to fogging
• Fogging can negatively affect vision during endoscopic surgery and increase
the risk of procedure failure
• It is also related to the road safety when it forms on the windshields
of a moving vehicle and helmet visor of a motorcyclist .
• It also reduces the efficiency of solar panels.
Scattering of light due to fog
Changing Environmental
Conditions
Modifying Surface
Properties

5. FUNDAMENTAL ASPECTS
SURFACE TENSION AND ENERGY
• The difference between the forces experienced by a molecule
on the surface and one in the bulk droplet gives rise to the
water surface tension of the water.
• Surface energy is a measure of this excess energy exists at the
material surface, compared to its bulk.
• Low surface energy of a material having low adhesive force is
regarded as hydrophobic material
• High surface energy is regarded for hydrophilic material.
The cohesion forces and surface tension acting on the
water droplet on solid surface

6. WETTABILITY
• Wettability is the ability of a liquid to be in contact with a solid
surrounded by other medium (liquid or gas).
• Young's equation describes the wettability of a fixed and smooth
substrate:
hydrophilic surface (10◦ < θ < 90◦),
superhydrophilic surface (0◦ < θ < 10◦);
hydrophobic surface (90◦ < θ < 150◦)
superhydrophobic surface (150◦ < θ < 180◦).
Surface energies created from interaction
of water droplet on a solid surface.
Young’s Equation :-
CHEMISTRY
• The wetting behavior of a material surface depends on the quantity of polar groups .
• These polar groups have hydrophilic functionalities .
• On the other side, less polar groups will result in hydrophobicity

7. Superhydrophilic antifogging coatings
• The superhydrophilic surfaces can show effective antifogging
performance due to their ability to form a hydration layer,
significantly reducing the droplets-caused scattering light and
enhancing the transmission light.
• In the case of superhydrophilicity, the water thin film
represents a transparent layer that does not refract the incident
light.
• Hygroscopic swelling takes place.
• Materials used : Polysaccharide polymers are famous for their
strong hygroscopic ability owing to the amounts of polar groups
periodically arranged alone leading chains, including OH, NH2,
COOH
STRATEGIES TO ANTIFOGGING PROPERTY

8. Superhydrophobic antifogging coatings
• Upon contacting a superhydrophobic surface, the water droplets tend to
leave it upon rolling by gravity-driven force.
• The surface roughness caused by the multiscale micro−
/nanostructure also plays an important role in superhydrophobic
surfaces
• water droplets cannot be removed from substrates until they have
grown above a critical size. Therefore, an antifogging induction
period is inevitable for superhydrophobic surfaces, although that may
be very short.
• Typical creature examples showing spectacular water-repellency
are summarized in such as lotus leaf , fly-eye , fish-scale, beetle.
• Materials used : The hedgehog-shaped polydimethylsiloxane
(PDMS), 3-sulfopropyl methacrylate potassium (SPMA), 2-
acrylamido-2-methyl propane sulfonic acid (AMPS)
Lotus leaf effect

9. Hygroscopic antifogging coating
• Recently, various hygroscopic coatings composed of hydrophilic and hydrophobic segments
have exhibited excellent antifogging performances.
• The synergy of two functional components makes coatings stable hygroscopic capacity to
water molecules in the surrounding environment.
• Thus, the choice and the proportion of two monomers are critical to endowing the coating to
hold the unique antifogging performances
• The familiar hydrophobic polymers in the hygroscopic coatings are mainly fluoride, alkane,
and siloxane.

10. MATERIAL OF ANTIFOGGING COATINGS
POLYMER COATINGS
• Recently, with the advances in polymer and materials and the surface microstructure,
versatile polymeric antifogging coatings have been commonly applied to the substrates to
adjust the wetting properties of the surfaces to achieve fog-repellency.
• Materials for antifogging coatings
a) Petroleum-based polymers : polyethers, polyvinyl, polyacrylates, polyacrylamindes,
polymethacrylates are used because of their excellent processability and physical
properties like flexibility, transparency and ductility.
b) Bio-inspired materials and structures : natural polysaccharide-based polymers like
cellulose and chitosan have made significant processes in antifogging coatings due to their
multifunctional and eco-friendly performances. Inspired by mussels and barnacles, the
polymeric coatings containing polyphenol groups have shown solid adhesion to universal
substrates.

11. INORGANIC COATINGS
• Most inorganic materials utilized in antifogging applications are ceramics or
metal oxides. It is well known that metal oxides are generally hydrophilic
because of metal cations, oxygen anions, and/or hydroxyl groups existed on
the surface.
• Inorganic coatings can be divided into two types based on their nature of
wetting:
a) Intrinsic wettability : includes materials that are naturally hydrophilic, such
as silicon dioxide SiO2, zirconium dioxide (ZrO2), indium tin oxide or ITO ,
and graphene oxide (GO).
b) Photoinduced Wettability : includes materials that are photo responsive,
such as TiO2, ZnO, and Bi2O3
• Hydrophilic metal oxides can be modified to increase their surface
superhydrophilicity by doping, treating, or mixing them with other metal
oxides
Photoinduced wettability
mechanism of TiO2

13. CONCLUSION
• In contrast to superhydrophilic surfaces, antifogging applications of superhydrophobicity is less
used because superhydrophobic surfaces must be tilted to roll off concentrated droplets, the
manufacturing procedures are more complex and time-consuming, and water-repellent materials
are not attached to the underlying substrate.
• Introducing hydrophobic segments in the hydrophilic polymer network endows the films with
mechanical stability and eliminates the swelling of superhydrophilic coatings caused by exceeding
absorbed water.
• The inorganic materials have potential for more durable coating compared to polymer-based
coating and hence these coatings should be more explored .

14. REFERENCES
• Xiaodan Gong, Haojie Yu * , Li Wang, Xiaowei Liu, Shuning Ren, Yudi Huang, Zhikun Huang,
Recent progress in the mechanisms, preparations and applications of polymeric antifogging
coatings , Advances in Colloid and Interface Science 309 (2022) 102794
• Izzati Fatimah Wahab, A.R. Bushroa , Soon Wee Teck , Taium Tasneem Azmi , M.Z. Ibrahim ,
J.W. Lee , Fundamentals of antifogging strategies, coating techniques and properties of
inorganic materials; a comprehensive review, journal of materials research and technology
2023;23:687 e714, 238-7854/2023 The Authors. Published by Elsevier B.V.
• https://en.wikipedia.org/wiki/Anti-fog (accessed on 31-03-2023)
• www.advancednanotechnologies.com/anti-fog-coating-the-mechanism-and-application/
(accessed on 30-03-2023)

15. THANK YOU!