SELF-CLEANING GLASS and ELECTROCHROMIC GLASS UNIVERSITÀ DEGLI STUDI DI LECCE Corso di laurea in...
-
date post
22-Dec-2015 -
Category
Documents
-
view
230 -
download
0
Transcript of SELF-CLEANING GLASS and ELECTROCHROMIC GLASS UNIVERSITÀ DEGLI STUDI DI LECCE Corso di laurea in...
SELF-CLEANING GLASSSELF-CLEANING GLASSandand
ELECTROCHROMIC GLASSELECTROCHROMIC GLASS
UNIVERSITÀ DEGLI STUDI DI LECCECorso di laurea in Ingegneria dei Materiali
A.A. 2001/2002
Scienza e Tecnologia dei Materiali Ceramici
Professore
Dott. Antonio Licciulli
Studente
Daniela Lisi
SELF-CLEANINGSELF-CLEANINGGLASSGLASS
SUMMARYSUMMARY
HISTORY
TITANIUM DIOXIDE
SELF-CLEANING SURFACE
PHOTOCATALYSIS
HYDROPHILICITY
SUPER-HYDROPHILICITY
SELF-CLEANING WINDOWS
HISTORYHISTORY
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 TiO2 electrodes 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 TITANIUM DIOXIDE
SELF- CLEANING and ANTIFOGGING functions
PHOTOCATALYST
HYDROPHILIC
RUTILE
Density: 4,2 g/ccRefractive Index: 2,76
ANATASE
Density: 4,2 g/ccRefractive Index: 2,52
TITANIUM DIOXIDE TITANIUM DIOXIDE
TITANIUM DIOXIDE TITANIUM DIOXIDE
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 TITANIUM DIOXIDE
SELF-CLEANING SURFACESELF-CLEANING SURFACE
TO CLEAN SURFACE OF BUILDING MATERIALS CAUSES:
Considerable trouble.
High consumption of energy.
Chemical detergents.
High costs
TO REALIZE SELF-CLEANING MATERIAL SURFACES THERE ARE THREE PRINCIPAL WAYS :
Super-hydrophobicity.
Photocatalysis.
Super-hydrophilicity and hydrophilicity
SELF-CLEANING SURFACESELF-CLEANING SURFACE
HYDROPHOBICITYHYDROPHOBICITY
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.
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.
CONTACT ANGLE
HYDROPHOBICITYHYDROPHOBICITY
HYDROPHOBICITYHYDROPHOBICITY
SUPER-HYDROPHOBICITYSUPER-HYDROPHOBICITY
The LOTUS EFFECT
PHOTOCATALYSIS PHOTOCATALYSIS
The acceleration of the rate of a photoreaction by the presence of a catalyst (semiconductor particle).
WHAT IS IT?
WHAT IS a SEMICONDUCTOR SOLID?
PHOTOCATALYSISPHOTOCATALYSIS
HOW DOES PHOTOCATALYTIC SEMICONDUCTOR WORK?
PHOTOCATALYSISPHOTOCATALYSIS
TiOTiO22 AS PHOTOCATALYST AS PHOTOCATALYST
DhD
AeA
ehhTiO2
HOHhOH2
-
22 OeO
OXIDATION-REDUCTION REACTION ON THE SURFACE OF TIO2
TiOTiO22 AS PHOTOCATALYST AS PHOTOCATALYST
IT IS COMPETITIVE BECAUSE:
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.
TiOTiO22 AS PHOTOCATALYST AS PHOTOCATALYST
PRACTICAL APPLICATIONS
TiOTiO22 AS PHOTOCATALYST AS PHOTOCATALYST
HYDROPHILICITYHYDROPHILICITY
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.
HYDROPHILICTYHYDROPHILICTY
HYDROPHILICTYHYDROPHILICTY
MECHANISM OF PHOTO-INDUCED HYDROPHILICITY
HYDROPHILICTYHYDROPHILICTY
a) Upon UV illumination
b) In the dark
TIME DIPENDENCE OF THE WATER CONTACT ANGLE IN AMBIENT ATMOSPHERE
SUPER-HYDROPHILICITY
SUPER-HYDROPHILICITY
STEP 1STEP 1STEP 2STEP 2STEP 3STEP 3STEP 4STEP 4
SCHEMATIC DIAGRAM OF SUPER-HYDROPHILICITY MECHANISM
SELF-CLEANING WINDOWSSELF-CLEANING WINDOWS
SELF-CLEANING WINDOWSSELF-CLEANING WINDOWS
SunClean Glass
SunClean Glass
SELF-CLEANING WINDOWSSELF-CLEANING WINDOWS
SELF-CLEANING WINDOWSSELF-CLEANING WINDOWS
Pilkington Activ™
SGG AQUACLEANSGG AQUACLEAN
SELF-CLEANING WINDOWSSELF-CLEANING WINDOWS
ELECTROCHROMICELECTROCHROMICGLASSGLASS
SUMMARYSUMMARY
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.
Optical switching materials can be used for windows where optical and thermal modulation is required.
OPTICAL SWITCHING TECHNOLOGYOPTICAL SWITCHING TECHNOLOGY
to control the flow of light and heat into and out of window, according to an energy management scheme.
THE PURPOSE IS:
OPTICAL SWITCHING TECHNOLOGYOPTICAL SWITCHING TECHNOLOGY
a large change in optical properties upon a change in either light intensity, spectral composition, heat, electrical field, or injected charge.
THE BASIC PROPERTY IS:
OPTICAL SWITCHING TECHNOLOGYOPTICAL 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.
OPTICAL SWITCHING TECHNOLOGYOPTICAL SWITCHING TECHNOLOGY
SMART WINDOWS SMART WINDOWS
Electrochromic windows change the light transmittance, transparency, or shading of windows in response to an environmental signal.
SMART WINDOWSSMART WINDOWS
HOW ECDs WORK?
A voltage applied across the transparent conducting oxide layers causes hydrogen or lithium anions (A+) to be injected into the electrochromic layers.
SMART WINDOWSSMART WINDOWS
HOW ECDs ARE MADE?
SMART WINDOWSSMART WINDOWS
ELECTROCHROMIC MATERIAL PERFORMANCE OBJECTIVES ARE:
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 WINDOWSSMART WINDOWS
GLASS/ITO/NiO/Inorganic Electrolyte/WO3/ITO/GLASS
Li) H, (M blue) (deep3
WOx
MxMxe(clear)3
WO
- xe (gray)x
NiO(OH)xOH(clear) NiO
SMART WINDOWSSMART WINDOWS
GLASS/ITO/NiO/Inorganic Electrolyte/WO3/ITO/GLASS
SMART WINDOWSSMART WINDOWS
GLASS/ITO/NiO/Inorganic Electrolyte/WO3/ITO/GLASS
SMART WINDOWSSMART WINDOWS
GLASS/ITO/PANI/PB/PAMPS/WO3/ITO/GLASS
SMART WINDOWSSMART WINDOWS
GLASS/ITO/PANI/PB/PAMPS/WO3/ITO/GLASS
SMART WINDOWSSMART WINDOWS
ECDs as ENERGY SOURCE
SMART WINDOWSSMART WINDOWS
ECDs as ENERGY SOURCE
THE SOLUTION THE SOLUTION SageGlass®SageGlass®
THE SOLUTION - SageGlass®THE SOLUTION - SageGlass®
THE SOLUTION - SageGlass®THE SOLUTION - SageGlass®
THE SOLUTION - SageGlass®THE SOLUTION - SageGlass®