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UNIVERSITÀ DEGLI STUDI DI LECCE Corso di laurea in Ingegneria dei Materiali A.A. 2001/2002 Scienza e Tecnologia dei Materiali Ceramici. SELF-CLEANING GLASS and ELECTROCHROMIC GLASS. Professore Dott. Antonio Licciulli. Studente Daniela Lisi. SELF-CLEANING GLASS. SUMMARY. HISTORY.

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self cleaning glass and electrochromic glass

UNIVERSITÀ DEGLI STUDI DI LECCE

Corso di laurea in Ingegneria dei Materiali

A.A. 2001/2002

Scienza e Tecnologia dei Materiali Ceramici

SELF-CLEANING GLASSandELECTROCHROMIC GLASS

Professore

Dott. Antonio Licciulli

Studente

Daniela Lisi

summary
SUMMARY
  • HISTORY
  • TITANIUM DIOXIDE
  • SELF-CLEANING SURFACE
  • PHOTOCATALYSIS
  • HYDROPHILICITY
  • SUPER-HYDROPHILICITY
  • SELF-CLEANING WINDOWS
history
HISTORY
  • The late 1960s: the University of Tokyo research photoelettrochemical solar cells. The solid-state photovoltaic device has become the technology of choice.
  • 1972: Fujishima and Honda discovered the photocatalytic splitting of water on TiO2electrodes without using electricity.
  • 1977: Professor Allen J. Bard and co-workers at the University of Texas first examined the possibilities of using TiO2 to decompose cyanide in water. Many important fundamental results concerning TiO2 photocatalytic reaction have been clarified by such intensive works.
  • The late 1990s: Pilkington, PPG, SSG patent SELF-CLEANING windows.
titanium dioxide

PHOTOCATALYST

SELF- CLEANING and ANTIFOGGING functions

  • HYDROPHILIC
TITANIUM DIOXIDE
slide6

ANATASE

  • RUTILE

Density: 4,2 g/cc

Refractive Index: 2,76

Density: 4,2 g/cc

Refractive Index: 2,52

TITANIUM DIOXIDE

slide8

White pigment in paints, cosmetics and foodstuffs.

  • Semiconductor transparent in the visible region of the

spectrum.

  • Low costs material.
  • Chemically inert, non-toxic, biocompatible.

TITANIUM DIOXIDE

self cleaning surface

Considerable trouble.

  • High consumption of energy.
  • Chemical detergents.
  • High costs
SELF-CLEANING SURFACE

TO CLEAN SURFACE OF BUILDING MATERIALS CAUSES:

slide10

Super-hydrophobicity.

  • Photocatalysis.
  • Super-hydrophilicity and hydrophilicity

SELF-CLEANING SURFACE

TO REALIZE SELF-CLEANING MATERIAL SURFACES THERE ARE THREE PRINCIPAL WAYS:

hydrophobicity
HYDROPHOBICITY

Hydrophobic materials ("water hating") have little or no tendency to adsorb water and water tends to "bead" on their surfaces (i.e., discrete droplets). Hydrophobic materials possess low surface tension values and lack active groups in their surface chemistry for formation of "hydrogen-bonds" with water.

slide12

HYDROPHOBICITY

CONTACT ANGLE

For a given droplet on a solid surface: the contact angle is a measurement of the angle formed between the surface of a solid and the line tangent to the droplet radius from the point of contact with the solid.

super hydrophobicity
SUPER-HYDROPHOBICITY

The LOTUS EFFECT

photocatalysis
PHOTOCATALYSIS

WHAT IS IT?

The acceleration of the rate of a photoreaction by the presence of a catalyst (semiconductor particle).

slide16

PHOTOCATALYSIS

WHAT IS a SEMICONDUCTOR SOLID?

slide17

PHOTOCATALYSIS

HOW DOES PHOTOCATALYTIC SEMICONDUCTOR WORK?

slide19

TiO2 AS PHOTOCATALYST

OXIDATION-REDUCTION REACTION ON THE SURFACE OF TIO2

slide20

A low-cost material is used as photocatalyst.

  • The reaction is quite fast at mild operating conditions

(room temperature, atmospheric pressure).

  • A wide spectrum of organic contaminants can be

converted to water and CO2.

  • No chemical reactants must be used and no side

reactions are produced.

TiO2 AS PHOTOCATALYST

IT IS COMPETITIVE BECAUSE:

slide21

TiO2 AS PHOTOCATALYST

PRACTICAL APPLICATIONS

hydrophilicity
HYDROPHILICITY

Also called hydrophilic, is a characteristic of materials exhibiting an affinity for water. Hydrophilic literally means "water-loving" and such materials readily adsorb water. The surface chemistry allows these materials to be wetted forming a water film or coating on their surface.

slide24

HYDROPHILICTY

MECHANISM OF PHOTO-INDUCED HYDROPHILICITY

slide25

HYDROPHILICTY

TIME DIPENDENCE OF THE WATER CONTACT ANGLE IN AMBIENT ATMOSPHERE

  • a) Upon UV illumination
  • b) In the dark
slide27

STEP 1

STEP 2

STEP 3

STEP 4

SUPER-HYDROPHILICITY

SCHEMATIC DIAGRAM OF SUPER-HYDROPHILICITY MECHANISM

slide29

SELF-CLEANING WINDOWS

SunClean Glass

slide30

SELF-CLEANING WINDOWS

SunClean Glass

slide31

SELF-CLEANING WINDOWS

Pilkington Activ™

summary34
SUMMARY
  • OPTICAL SWITCHING TECHNOLOGY
  • SMART WINDOWS
  • THE SOLUTION SageGlass®
optical switching technology
OPTICAL SWITCHING TECHNOLOGY

It changes the view of glazing from a FIXED element to a DYNAMIC one.

slide36

OPTICAL SWITCHING TECHNOLOGY

Optical switching materials can be used for windows where optical and thermal modulation is required.

slide37

OPTICAL SWITCHING TECHNOLOGY

THE PURPOSE IS:

to control the flow of light and heat into and out of window, according to an energy management scheme.

slide38

OPTICAL SWITCHING TECHNOLOGY

THE BASIC PROPERTY IS:

a large change in optical properties upon a change in either light intensity, spectral composition, heat, electrical field, or injected charge.

slide39

OPTICAL SWITCHING TECHNOLOGY

This optical change results in a transformation from highly transmitting state to a partly reflecting or absorbing state, either totally or partly over the solar spectrum.

smart windows
SMART WINDOWS

Electrochromic windows change the light transmittance, transparency, or shading of windows in response to an environmental signal.

slide41

SMART WINDOWS

HOW ECDs WORK?

slide42

SMART WINDOWS

HOW ECDs ARE MADE?

A voltage applied across the transparent conducting oxide layers causes hydrogen or lithium anions (A+) to be injected into the electrochromic layers.

slide43

continuous range in solar and optical transmittance, reflectance, and absorbance between bleached and coloured states;

  • contrast ratio (CR) of at least 5 a 1;
  • colouring and bleaching times (switching speed) of a few minutes;
  • switching with applied voltages of 1–5 V;
  • acceptable neutral colour;
  • large area with excellent optical clarity;
  • sustained performance over 20–30 yr;
  • acceptable cost ($100/m2);

SMART WINDOWS

ELECTROCHROMIC MATERIAL PERFORMANCE OBJECTIVES ARE:

slide44

SMART WINDOWS

GLASS/ITO/NiO/Inorganic Electrolyte/WO3/ITO/GLASS

slide45

SMART WINDOWS

GLASS/ITO/NiO/Inorganic Electrolyte/WO3/ITO/GLASS

slide46

SMART WINDOWS

GLASS/ITO/NiO/Inorganic Electrolyte/WO3/ITO/GLASS

slide47

SMART WINDOWS

GLASS/ITO/PANI/PB/PAMPS/WO3/ITO/GLASS

slide48

SMART WINDOWS

GLASS/ITO/PANI/PB/PAMPS/WO3/ITO/GLASS

slide49

SMART WINDOWS

ECDs as ENERGY SOURCE

slide50

SMART WINDOWS

ECDs as ENERGY SOURCE