Electroactive polymers
Three main kinds of materials
metals, plastics and ceramics.
w.wang 198 Preface
I am inclined to think that the development of polymerization is, perhaps, the biggest thing chemistry has done, where it has had the biggest effect on everyday life. The world would be a totally different place without artificial fibers, plastics, elastomers etc. Even in the field of electronics, what would you do without insulation? And there you come back to polymers again.--- Lord Todd, president of the Royal Society of London, quoted in Chem. Eng. News 58 (40), 29 (1980), in answer to the question, What do you think has being chemistry’s biggest contribution to science, to society?
From clothing to the artificial heart, polymers touch our lives as do no other class of materials, with no end in sight for new uses and improved products.
w.wang 199 Polymer Macromolecule
Out line of the science of large molecules
Polymers Biological materials Plant fiber, starch saccharin etc.
Plastics fibers, elastomers Nonbiological materials Rubber, wool, cellulose, silk and leather etc. w.wang 200 Some linear high polymer, their monomers, and their repeat units
Polymer Monomer Repeat Unit
CH2 CH2 CH2CH2 CH CHCl • Polyethylene CH2 CHCl 2 • Poly(vinyl chloride) CH3 CH3
CH2 C CH2 C
CH CH • Polyisobutylene 3 3 CH2 CH CH2 CH • Polystyrene
H N(CH2)5C OH N(CH2)5C
• Polycaprolactam (6- H H nylon) O O
CH CH 2 CH2 CH2 CH2CH CH2 CH2
• Polyisoprene (natural CH3 CH3 rubber) w.wang 201 Polymerization
• Step-reaction (Condensation) polymerization
• Radical chain (addition) polymerization
• Ionic and coordination chain (addition) polymerization
• Copolymerization
w.wang 202 Characterization for Analysis and Testing of Polymers -----Common Methods and Equipments
• Dynamic light scattering spectrometer- thermodynamics properties
• Mass spectrometry- structure of low-molecular- weight species
• Infrared Spectroscopy (IR) - structure
• Nuclear Magnetic Resonance Spectroscopy 1HNMR and 13CNMR -chain configuration, sequence distribution, and microstructure • X-ray diffraction analysis WAXD- the spatial arrangements of the atoms SAXS: larger periodicities • Light Microscopy (SALS)- spherulites or rod and phase-contrast
• Electron Microscopy and Electron Diffraction
• Scanning Electron Microscopy (SEM) and Transmission Electron Micrograph (TEM)
• Deferential Scanning Calorimetry (DSC)- thermal analysis
• Stress-strainw.wang properties in Tension 203 States of Polymer
Biological field liquid states how to make gel, film, fiber and composite etc. Polymers
sol- gel states artificial muscle, switch and smart window etc.
solid states film, fiber and container etc.
artificial muscle, switch and smart window etc.
w.wang 204 w.wang 205 (a) (b) X-ray diffraction patterns for unoriented (a) and oriented (b) polyoxymethylene (courtesy of E.S. Clark)
Ringed spherulites of poly(trimethylene Electro micrograph of a portion of a glutarate) observed in the optical microscope ringed spherulite in linear polyethylene between crossed polarizers (Keller 1959) (photograph by E.W. Fischer, from Geil 1963) w.wang 206 SAXS and WAXD patterns (end view) from polyethylene/carbon blend materials with the indicated compositions
w.wang 207 (a) Hv SALS photos of low and medium density polyethylene (c) Surface replica electron microscopy of Polytetrafluoroethylene (Teflon) with different heat treatments (b) and (d) and corresponding with Hv SALS (a), (c)
(b) Hv SALS photos with indicated draw ratiosw.wang (stretching direction is vertical) 208 Utilizing plastics for car components
Handle Poly(vinyl chloride) Proof , Seat polypropylene Poly(vinyl chloride) Air filter Phenol resin Bumper Polyamide Poly(vinyl chloride)
Bumper Tire Door handle Carpet Polypropylene Synthetic resin Polycarbonate Nylon Polycarbonate (styrene) Polyacetal
w.wang 209 Active materials sensing and responding to change of environment Environmental stimuli Response
♦ Temperature ♦ Phase ♦ Solvent, pH ♦ Shape ♦ Electric field ♦ Optics ♦ Magnetic field ♦ Mechanics ♦ Light or UV ♦ Permeation rates ♦ Recognition Flowers are sensitive to light This fish changes color according to the surroundings
w.wang 210 Polymers with electrical and electronic properties Conventional polymers (using Physical their strength, flexibility, elasticity, stability, mould Thermal
Polymers ability, dielectric properties, Chemical etc.) Specialty polymers Optical (using their electrical Electronic conductivity, photoconductivity, Electrical nonlinear optical effects, dielectric properties, etc.)
w.wang 211 Electroactive Polymer (EAP) Materials • Electric EAP --- PVDF-based Ferroelectric polymers
• Ionic EAP ---Electroactive polymer gels ---Ionomeric Polymer-Metal Composites
• Non-ionic EAP --- PVA-based
• Conductive Polymer ---PPy and PANI ---w.wang PEDOT and PEDOP based 212 Applications and application potentials
• Antenna and mirror
• Biomimetics and switching technologies ---Nafion, Flemion, poly(vinyl alcohol) (PVA) gel, conducting polymer and carbon nanotube actuator • Switching window, electromagnetic shutter and display technologies --Acrylamide and vinyl derivative copolymer, copoly(Aam/vdMG) gel and electrochromic polymer, ProDOT-(CH3) • Drug delivery system --- Polymer gel and Conducting polymer: e.g. polyacrylamide gel polypyrrole(PPy) • Sensor Nafion and polyaniline (PANI) w.wang 213 Applications
Comparison of energy storage capabilities of several dielectric materials and capacitors technologies
w.wang 214 Space mirror…
(b) Inflatable antenna experiment on orbit. The inflatable antenna was packaged into the reusable Spartan satellite (a) Echo 1 passive satellite (courtesy NASA). seen on the right (courtesy NASA).
(c) A space shuttle view of the L’Garde’s (d) Dielectric actuator demonstrated to inflatable antenna experiment (IAE). expand and relax (courtesy of R.Kornbluh w.wang and R.Pelrine, SRI International). 215 How they work? • Antenna
EAP w.wang 216 How they work?
(a) Principle of operation of dielectric elastomer actuators.
voltage off voltage on voltage off voltage on (b) Biaxially uniform prestrain (c) Anisotropic prestrain with and circular electrodes. linear electrodes.
w.wang 217 Dielectric actuator
w.wang Dielectric Actuator W.-C. 218Wang Dielectric actuator
w.wang Dielectric Actuator W.-C. 219Wang Snake-like actuator
w.wang 220 w.wang 221 Linear actuator
w.wang 222 Fish actuator
SRI w.wang 223 Walking robot
SRI w.wang 224 Animation
w.wang UCSD 225 How they work?
Without E-field With E-filed (b) Particle suspension forms chains when electric field is applied
(a) Bending of a polyacrylic acid gel rod sodium hydroxide. DC applied field, cathode (negative) at a bottom. Gel swells on the anode side and bends toward the cathode [Shiga, 1997] (c) Electrorheological fluid at reference (left) and activated state (right) [courtesy of ER Fluid Developments Ltd, UK] w.wang 226 Applications
(c) A photographic view of a human hand and (a) Facial muscle that produced skeleton as well as an emulated structure expression [Netter, 1995] for which EAP actuators are being sought [Courtesy of Garham Whiteley, Sheffield Hallam University, UK]
(d) Dynamic gestural figure (b) Smiling robot of Hidetoshi Akasaw w.wang with muscles exposed. 227 How they work?
Polymer Gels
Gel structure: • Solid phase - crosslinked polymer matrix • Liquid phase - solvent
Phase transition - discontinuous change of properties, size, shape, etc. under discrete change of environment
Molecular interactions - ionic, hydrophobic, hydrogen bonding, van der Waals
w.wang 228 How they work? Current applications: Medicine and Biotechnology
1) Drug delivery devices B
B B + B B stimulus B -
B B 2) Molecular separations
B C C B C B C B - stimulus + stimulus B filter B B C B B filter C B B C B C B C C recycle gel
w.wang 229 Study on several EAPs
(1) Poly(vinyl alcohol) (PVA) gel
(2) Nafion and Flemion
(3) Copoly(Aam/vdMG) gel
(4) Electrochromic polymer, ProDOT-(CH3)
w.wang 230 Material development
• Polyvinyl alcohol (PVA) gel:
- actuation in electric field by contraction and bending
- influence of structure to deformation: • molecular level
• macroscopic level Gold films Holder
- fastest response (<1s)
- low strength material
- high applicable voltage
w.wang 231 Influence of structure - molecular level • Degree of polymerization (DP) - 1400, 2100, 17900
25
20
15 E d ∆x 10 Strain (%) Strain DP1400 5 DP2100 x DP17900 0 0 200 400 600 800 E-field (V/mm) • Tacticity - atactic, syndiotactic
2.5 3.4 2.4 3.2 3 2.3 2.8 2.2 2.6 2.4
Thickness (mm) at-PVA (DP2100, 80min) 2.1 (mm) Thickness st-PVA (DP2000, 80min, heated) E = 290 V/mm 2.2 E = 310 V/mm 2 2 0 100 200 300 400 0 100 200 300 400 500 Time (s) w.wang Time (s) 232 Stress Generation
Cathode
Anode
w.wang 233 Mechanism of Electric Actuation • Dielectric liquid can be ionized upon high E-field j - current density I j = ρ⋅b ⋅E = ρ - charge density A b - charge mobility E = −gradφ E - electric field strength I - electric current ∇D = ρ A - surface of condenser plates φ - electric potential D - electric displacement
• Potential and electric field in dielectric material
3/ 2 εbA 2I φ(x) = φ(0) − x + E2 (0) − E3 (0) 3I εbA 1/ 2 2I E(x) = E2 (0) + x εbA w.wang 234 Mechanism of Electric Actuation • If the dielectric is liquid, Maxwell stress converts to fluid pressure
2 9ε V − V' x d - distance between electrodes p(x) ≈ 8 d d V = φ(d) V’ - ionization potential • Charge injection to the solvent (DMSO) in PVA gel, upon applied E-field OFF ON
O ∆ S d O
M S +
O D D S M D M M S SO D O M D D M S d O DMSO + + O DMSO
S
M
O D DMSO S + M O D S DMSO DMSO + M + D DMSO DMSO - PVA network • For the PVA gel having 96-98% liquid phase, solvent pressure is converted to gel stress, with the efficiency η
w.wang σ(x) = η⋅ p(x) 235 PVA gel actuator as a switch
Au sheet Gel Plastic film
Silicone film
Au sheets Glass substrate
(a) Schematic diagram (b) Top view of coated gel
w.wang 236 Application potential
DMSO Gel
Pupil
w.wang 237 Application potential
Carnivorous Plants
2mm 60 ms
w.wang 238 2 types of ion flux through membrane
Static ion flux Dynamic ion flux No current With current
E E 2e- 2e- + + + + + –++ + + –++ + + + + + Cu + + + + + + + + + Cu2+ + 2e- + + Cu2+ + 2e- + + + + + + + + + + Cu + + + + + + + Cu2+ Pt or Au electrode Cu metal Pt--Cu electrode + Na+ Redistribution of ions Ion flux with electrode reaction Electric current is charge current alone Electric current continuously flow M. Uchida, CIMS w.wang University of Washington 239 Comparison with Pt electrode
0.16
0.14
0.12 Pt-Cu 0.1 Pt-Li 0.08 Pt-Cu electrode with copper ion 0.06
curvature ) (1/mm V=1V 0.04
0.02
0 024681012 Time ( sec )
Pt electrode with Lithium ion w.wang 240 How it works? Nafion actuator array Material design: membranes of different thickness and gold electrodes After 2 plating cycles Nafion 117
7.8 µm
Nafion 115 After 3 and 6 plating cycles
8.2 µm 7.5µm Nafion 112
6.1 µm 16 µm
The depth of the fractal structure is mostly controlled by the plating conditions not by the amount of gold. w.wang 241 Nafion loop actuator and performance data
7
6 1.0 V 5mm 0.5 V 5 Off (b) 4
3 Force F (mN) Force F 2 On
1
0 F 01234 On Displacement d (mm) d Off (c) (a)
w.wang 242 Parallel device
OFF Positive (expand) Negative (Shrink)
10 9 8 1.0 V 7 0.5 V 6 5 4
Force ( mN ) 3 2 1 0 012345 w.wang Displacement ( mm ) 243 Summary • Actuation materials
Material Advantages Drawbacks AAm Large swelling ratio Low stiffness Slow response PAN Faster response Limited voltage range Higher stiffness PVA Fast response Large deformation Low stiffness Large voltage range Nafion Fast response High stiffness
AAm - acrylamide based PAN - polyacrylnitrile PVA - polyvinylalcohol w.wang 244 Smart System option with PAN fibers Smart system optionConcept with PAN fibers concept
5V, 0.5A 5V, 0.5A positive electrode: H+ is created Counter >acid condition, PAN fibers contract Metal electrode Metal Coated coated PAN PAN negative electrode: OH- is created water fibers fibers >basic condition, PAN fibers expand shrink expand
Example of possible Articulated rigid fin design structure = bone
Assembly of articulated bones and contractile actuators creates a Bundle of PAN conformable fin. fibers = muscle Many shapes are achievable.
w.wang 245 Smart system option with PAN fibers concept: mimic nature!
w.wang from www.kidshealth.org/misc_pages/bodyworks/bodyworks.html246 Applications potential
Artificial tactile feel display
Tadokoro et al. Kobe University, Japan w.wang 247 Applications Characteristics of IPMC Low voltage ~1V Bending mode of actuation Large displacement Soft Wet Ionic nature Small scale
Applications Micropump www.eamex.co.jp/index_e.html Catheter Robotfish actuator Gripper
www.eamex.co.jp/index_e.html
w.wang www.eamex.co.jp/index_e.html 248 Fleminon Fish
www.eamex.co.jp/index_e.html
w.wang 249 Applications Actuator arrays
http://voronoi.sbp.ri.cmu.edu/projects/prj_virtu http://bifano.bu.edu/tgbifano/Web/ www.sciam.com alvehicle.html %B5Valve.html
Electroactive polymer actuator arrays Low cost, low power consumption, large displacement, softness Polymer nature, compatible with wet environment
w.wang 250 How it works? Flemion actuator array
Actuator design: Flemion beam actuator for microwave switch
Microwave switch OFF ON
Actuator Contact pad Transmission line
Switch design: actuator above board and lifting contact pad in OFF stage. Contact pad resting against the TL in ON stage
Actuator With additional weight Transparency tie with copper pad
OFF stage TL
ON stage
w.wang 251 How they work? Actuator Array
Application: Antenna for satellite based Internet connection
Microwave switches
Phase Shifters Waveguide wave gap
Dielectric Material Nafion Nafion membrane membrane actuator actuator w.wang 252 3x3 Array from Nafion 112 with gold electrodes and TEA ion: Patterning
We use hydrophobic masks to selectively swell the membrane with the gold complex Nafion membrane
Silicon Gold rubber mask complex solution
Gold is plated by reduction of the gold complex Reductant Gold metal plated at the surface Na2SO3
Gold Phenantroline complex + [Au(Phen)Cl2]
w.wang 253 How it works?
3 2 1 0 -1 1 6 11 16 21 26 31 -2
Voltage (V) -3 0.2 0.1 0 -0.1 current (A) current -0.2 0.6 0.4 0.2 relaxation relaxation 0 -0.2 1 6 11 16 21 26 31 Displacement (mm) Displacement actuation actuation Voltage, current and displacement versus downward initial upward time of the active cell profile profile profile
w.wang 254 At time = 0sec How they work? Voltage goes Application: Conformable fin for Submarine from 0 to 2V 2s 5s Nafion is an Ion Exchange Polymer Membrane. Negative charges are attached to the polymer backbone. Next to each negative charge is a positive 180 micron thick Counter ion and some water molecules. If we apply 0s 2s 5s an electric field across Nafion the positive ions move and the whole membrane starts moving. This works best if the membrane is fully hydrated. 125 micron thick Therefore Nafion actuators work best in water
0s 0.7s 2s 50 micron thick
w.wang 255 Carbon nanotube actuator 4V, strain 0.8%, stress 512GPa Baughman et al. Science 284(5418),1999
0
Wallace et al, 2001,SPIE w.wang 256 Conducting Polymers
• Insulating polymers: familiar uses include cable sheathings, dielectric layers and films as in capacitors, printed circuit substrates.
w.wang 257 Conduction mechanisms
Conduction band Energy Forbidden gap
Valence band
Conductor Semiconductor Insulator
hole electron w.wang Representation of energy band for metal semiconductor and insulator 258 (Sm-1) Conductive polymers 108 Graphite 106 Copper Iron, mercury metals 4
10 Carbon black s
e
x e
102 l
p m
0 o c
10 germanium
l
a t
10-2 e
m
silicon r e -4 10 m
semiconductors
y l Carbon black composites Carbon black Polyacetylene derivatives and Polypyrole derivatives -6 o
10 Silver bromide P phthalocyanines Poly(p-phenylene) derivatives 10-8 derivatives Polyimide glass 10-10 diamond -12 insulators 10 Polyphenylene sulphide derivatives nylon 10-14 sulphur polyethylene 10-16 Conductivities of various elements, compounds and polymers w.wang 259 PolyPyrolysis
O O
O O n
w.wang 260 Polyacetylene
H H H o C C C C cis -78C C C C C H H H H-C=C-H
H H H H 150Co C C C C C C C C trans
H H H H
w.wang 261 Difference structure between polyethylene and polyacetylene
ethyleneethylene Polyethylene
(a) Polyactylene thin film
acetylene Polyacetylene
w.wang 262 (b) Polyactylene thick film How they work? SP3
Polyethylene
(a) π-bond σ-bond
C-C double bone
(b)
w.wang π-bond Polyactylene 263 Polyacetylene after doping
w.wang 264 Polyparaphenylenes
AlCl3, CuCl2 35 oC n
w.wang 265 Polypyrrole
H H N N
N N H H
w.wang 266 Polyaniline
H H H N N N
Polyphenylene sulfide
SSS
w.wang 267 Active drug delivery system and actuator
B
B B + B B stimulus B - Wallace et al, 2001,SPIE w.wang B B 268 Sensing fiber Wet-spun polyaniline (PANI) fiber
Cross-section micro-structure w.wang Yang et al. 2001 269 Clothing technology
w.wang 270 Applications of EC Polymer
Present Commercial Products:
• Plastic rechargeable batteries Polyactylenes (PA) and polyanilines (PAn) cell phone, back-up power source for personal computer, solar-powered calculator etc
• Sensors Polypyrrole (PPy), PA, Polythiophone, Polyparaphenylenes (PPP) and PAn Sensing vapours of nitromathane, toluene, benzene, methanol and water Determining the concentration of ions in solution Electrochemical biosensors
•Shielding PAn etc Electrostatic discharge and electromagnetic interference/ratio-frequency interference applications
w.wang 271 Applications of Conductive Polymer
• Printed circuit boards Flexible insulating substrate with a conducting pattern that could form the basis of printed circuit board Complex multilayer board
• Condenser
• Various semiconductor devices
• Electrochromic displays, smart window
• Solid electrolyte (doped polypyrrole) and etc
w.wang 272 Applications of EC Polymer
Present research
• Diode
• Display for mini television
Future
• Electronics Molecular diode, molecular computer and electroluminescence and etc.
w.wang 273 Design of smart window technology
w.wang 274 Outline
1. Background 2. Color changeable gel 3. New design of electrochromic color changeable device 4. Mechanism for color change 5. Preparing three parts for the device 6. Assembly 7. Testing and analysis of performance •Transmittance • Optical switching speed • Repeatability (Electrochemistry study) • Voltage effect on color change speed • Voltage effect on color change degree • Temperature dependence 8. Application potentials w.wang 275 Background
Liquid crystal Polymer gels Inorganic electrochromic Liquid materials Difficulty in processing Electrochromic Very fast (EC) polymer e.g. WO3 Many colors Liquid and solid High cost Difficulty in processing Slow Small size Blue Narrow angle ? Low cost Big size Wide angle long-term stability rapid switching large changes in transmittance w.wang 276 ～～
UVor E (H C) N C N(CH ) (H C) N C N(CH ) +OH- 3 2 3 2 dark or E 3 2 + 3 2 OH
A + H2O A A A+
A H2O A+ H2O A H O A H2O + 2 A A A+ A A+ A A+ H2O H2O A A+ A+ H2O H2O Machanism for color and volume change of copoly(Aam/vdMG) gel under UVor pH(Electric current) where A and A+ represent the neutralized and the ionized vdMG, respectively
10ｍｍ
Changing concentration of vdMG in the gel to control the degree of color change, color changed under E-current, 1.5A,5V at 20 oC w.wang 277 RESULTS AND DISCUSSION
• Color change speed
stimuli UV pH E-current UV & E-current E-current & Na2SO4 E-current & AAm gel
light green to dark green 3 min 1.5 min 40 s 30 s 23 s 19 s dark green to light green 15 h 2min 60 s 60 s 23 s 19 s
Previous results, Irie et al. present results
• Effect of gel thickness on actuation speed under applied E-current Employed the most effective setup given in above
thickness 1.0mm 0.75mm 0.50mm 0.25mm 0.125mm light green to dark green 25s 19s 15s 11s 9s dark green to light green 25s 19s 15s 11s 9s
w.wang 278 Schematic diagram of device design using color changeable EC polymers Three-layer scheme:
ITO ITO
Cathodic EC Polymer Cathodic EC Polymer
Solid electrolyte Solid electrolyte
Anodic EC Polymer Anodic EC Polymer
ITO ITO
Transparent Colored
Two-layer scheme:
ITO ITO
Cathodic EC Polymer Cathodic EC Polymer
Solid electrolyte Solid electrolyte
counterelectrode Anodiccounterelectrode EC Polymer
Transparent Colored w.wang 279 Schematic diagram of mechanism for color
change of cathodic EC polymer, PProDOT-Me2
O O O O
S S Cathodic EC polymer S S n
O O O O
- + -e - Dark blue Transparent p-Doped state Neutral state + e- Li+ + + - - - Li Li ClO4 ClO4 ClO4 gel gel
- - - + + + ClO4 ClO4 ClO4 Li Li Li
- - - + + +
Au-patterned thin layer w.wang 280 Schematic diagram of device design using color changeable EC polymers Three-layer scheme:
ITO ITO
Cathodic EC Polymer Cathodic EC Polymer
Solid electrolyte Solid electrolyte
Anodic EC Polymer Anodic EC Polymer
ITO ITO
Transparent Colored
Two-layer scheme:
ITO ITO
Cathodic EC Polymer Cathodic EC Polymer
Solid electrolyte Solid electrolyte
counterelectrode Anodiccounterelectrode EC Polymer
Transparent Colored w.wang 281 Synthetic Route of Monomer,ProDOT -Me 2 for Cathodic EC Polymer
S
MeO OMe OHOH pTSA OO + Toluene 110 o C overnight S
w.wang 282 3
S 1 2
OO 1 2 3
9.00 8.00 7.00 6.00 5.00 4.00 3.00 2.00 1.00 0.00 -1.00 ppm
NMR spectra of cathodic monomer, ProDOT-(CH3)2 The number given over each NMR spectrum peak corresponds
to the number given to the proton of ProDOT-(CH3)2 as shown in the left
w.wang 283 SyntheticSynthetic RouteRoute ofof ECEC Monomer,Monomer, XDOPXDOP -Benzylation of Dimethyl Iminodiacetate
MeOH N Benzyl Bromide HO2C N CO2H MeO2C CO2Me H H
1 2
HO OH MeO OMe MeO CCON Me MeONa 2 2 + CO Me Ph O O MeO2C N 2
Ph
3 4 5 w.wang 284 Synthetic Route of EC Monomer, EDOP
HO OH Br Br 6a
MeO C CO Me Br Br 2 N 2 + 6b
MsO OMs Ph 6c 5
O O O O
MeO C CO Me 2 N 2 MeO2C N CO 2Me
H Ph 8a 7 a
O O O O
HOOC N COOH N
H H w.wang 9a 10a 285 Synthetic Route of EC Monomer, ProDOP-(CH3)2
HO OH Br Br 6a
MeO C CO Me Br Br 2 N 2 + 6b
MsO OMs Ph 5 6c
O O O O
MeO C CO Me 2 N 2 MeO2C N CO2Me
H Ph 8c 7c
O O O O
HOOC N COOH N
H H w.wang 9c 10c 286 Schematic diagram of device design using color changeable EC polymers Three-layer scheme:
ITO ITO
Cathodic EC Polymer Cathodic EC Polymer
Solid electrolyte Solid electrolyte
Anodic EC Polymer Anodic EC Polymer
ITO ITO
Transparent Colored
Two-layer scheme:
ITO ITO
Cathodic EC Polymer Cathodic EC Polymer
Solid electrolyte Solid electrolyte
counterelectrode Anodiccounterelectrode EC Polymer
Transparent Colored w.wang 287 PMMA based gel electrolyte for EC smart windows
PMMA/LiN(CF SO ) /PC 3 2 2 PMMA/LiClO4/PC wt% 20/10/70 wt% 20/10/70
PMMA/LiN(CF3SO2)2/PC+EC PMMA/LiClO4/PC+EC wt% 20/10/70 (PC:EC=1:1 on volume) wt% 15/5/80 (PC:EC=1:1 on volume)
w.wang 288 TransmittanceTransmittance ofof IndicatedIndicated GelGel ElectrolyteElectrolyte
100 90.4 89.1 88.8 88.6 88.3 87.4 88.4 89.6 89.4 89.7 90 80 70 60 50 40 30 20 10 % Transmittance 0
0 2 0 20 2 E 2 2 2 2 21/ 0 14/ 21/0 25/ 8/ 19/ 8/ 9/ 9/ 3)2 5/6/0 4 8/ 4 )2 SS SLID 3)2 A ClO lO GL Li SO2CF R C/ SO2CF3)2 N( SO2CF Li C+P N(SO2CF3 N( E ACN/LiC Li C/ Li P 1 CLEA C/ C/ P P ACN/LiN(SO2CF3)2 5/2/02 + L(20ml)+PC/LiClO4 9/26/0 ACN/LiN(SO2CF3)2EC+ 8/14/02 l) C+ B E G
L(40ml)+PC/LiN(L(20m B B G G w.wang Electrode 289 Schematic diagram of device design using color changeable EC polymers Three-layer scheme:
ITO ITO
Cathodic EC Polymer Cathodic EC Polymer
Solid electrolyte Solid electrolyte
Anodic EC Polymer Anodic EC Polymer
ITO ITO
Transparent Colored
Two-layer scheme:
ITO ITO
Cathodic EC Polymer Cathodic EC Polymer
Solid electrolyte Solid electrolyte
counterelectrode Anodiccounterelectrode EC Polymer
Transparent Colored w.wang 290 Design of Pattern for Carbon and Gold Based- Counterelectrode
Top View Glass Diameter 4 inch
Side View Carbon ITO Glass
(a) Carbon-based (b) Au-based w.wang 291 TransmittanceTransmittance ofof IndicatedIndicated ElectrodeElectrode
100 90 80 70 60 50 40 30 % Transmittance 20 10 0 C 6µ1.0 C 6µ1.5 C 6µ0.1 C 10µ1.5 C 20µ1.0 C 20µ1.5 C 20µ2.0 Au 25µ1.5 Au 15µ1.0 Au 50µ2.5 Au Au 50µ1.5 Au Au 100µ1.5 Au Hitachi glass Electrode w.wang 292 Assembly of EC polymer device for transmittance control in visible region, carbon-based counterelectrode
Transparent insulating substrate
Transparent gel ITO transparent electrolyte film Carbon patterned thin layer EC polymer film ITO transparent film
w.wang 293 Assembly of EC polymer device for transmittance control in visible region, Au-based counterelectrode
Transparent insulating substrate
ITO transparent film
EC polymer Transparent gel electrolyte film
Au patterned thin layer
w.wang 294 Color Change of EC Polymer Device Using Au Patterned glass as a Counterelectrode
1s
(a) 2.5V, Transparent (b) - 2.5V, Dark blue
w.wang 295 Color Change of EC Polymer Device Using Graphite Patterned ITO glass as a Counterelectrode
1s
(a) 2.5V, Transparent (b) - 2.5V, Dark blue
w.wang 296 Enhanced Contrast Ratio in Cathodic EC Polymer Device Based on Au patterned counterelectrode
90 80 Bleached 70 60 Fully reduced 50 Fully oxidized 40 30 20 Colored
Transmittance/% 10 0 190 290 390 490 590 690 790 Wavelength/nm
Visible spectrum collected in transmittance mode of a cathodic EC polymer device in fully transmitted and fully colored states
w.wang 297 Enhanced Contrast Ratio and Rapid Switching in Cathodic EC Polymer Device
(a) Au-based
(b) Carbon-based
Optical switching for the devices based on indicated
w.wangcounterelectrodes monitored at wavelength 580nm 298 Photographs of potential effect on color changing degree
Blue EC polymer device/Gold counterelectrode
0V -1.0V -1.5V -2.0V - 2.5V
Red EC polymer/ ITO glass
-0.15V -0.2V -0.25V -0.3V - 0.35V Color changing speed is same, less than 1s w.wang 299 BlueBlue ECEC FilmFilm ComparisonComparison
Original Blue New Blue
w.wang 300 New red color
w.wang 301 10a
w.wang 302 10c best
w.wang 303 A circular smart window with rubber seal
EC polymer deposited ITO glass _ Gel electrolyte + _ Sealing rubber +
Smart window Carbon patterned ITO glass
w.wang 304 An electrochromic window
A simple electrochromic display
w.wang Ishihara et al ,2001 305 Application Potential
Commercial air plane Special air craft http://www.boeing.com w.wang 306 Smart window
w.wang http://windows.lbl.gov/materials/chromogenics 307 Future works
Several new ideas…
1. Carbon nanotube actuator
2. Conducting polymer • Bio-related actuator drug delivery system, e.g. polypyrrole • Sensing clothing Body stress, signal, e.g. polyaniline(PANI) fiber
3. Special fiber
w.wang 308 All-solid-state Electrochromic Glazing
WO3, high durability but low contrast ratio (40:1)
Aircraft side window
F. Beteille (France) The SPIE Conference on Switchable Materials and Flat Panel Displays SPIE Vol. 3788 pp.70-73 (July 1999) w.wang 309 E-ink
How they work?
w.wang Scientific American November 2001 pp,51-54 310 Flexible active-matrix electric ink display - Electric paper
White state Dark state
Nature 136 p.136 (2003)
w.wang 311 Shape memory polymer
w.wang 312 Camouflage skin of Octopus
Original Camouflaged in white
w.wang 313 Application potential --- Wearable smart sensors/actuator
Day time Day time Night Land warrior Taking a break Moving to the position
w.wang 314 Conclusions • From “hard” to “soft” technology
• EAP - structure, processing, sensing, actuation… …all in one • Advantages for actuator applications: - light weight - energy storage - viscous damping -low cost • Challenges: - Materials development w.wang - Integration into smart devices and structures 315