(Update03) EC

 
Electrochromic Material
 
 
 
Inspiration:
 
As I understand, we are not supposed to be dealing with the same material that has been attempted, (eg, thermochromic), althought it is commercially available and feasible to control (We haven't start to work on hand to see whether the cool down problem could be solved. However, ideally, it could be implemented applying the similar method as used by battery tester)
 
So it is essential that we find out some other possible materials.
 
and Electrochromic Material comes in its way.
 
Electrochromic materials are those that exhibit an optical change upon reduction (gain of electrons) or oxidation (loss of electrons).
 
 
Readings and thoughts 
 
1. The working theory of Electrochromic
 
1. small bias (typically 1-2V)
2. oxidation and reduction with loss and gain of electrons. transmit from strong light absorber in one redox state to colorless in another
3. electrode - coated oxide layer
4. electrolyte - gel/solid; advantage: function as thin layer of laminators, lessen the deformation and leakage problem.
5. ECM1red: colourless-to-coloured upon oxidation (loss of electrons), @ positive electrode (anode)
    ECM2ox: colourless-to-coloured upon reduction (gain of electrons), @ negative electrode (cathode)
6. advantages:
    - viewing angle of 180 degree (compared with LC), does not require POLARIZERS
    -  inherent color, continuous gray scale, and low average power consumption
    -  life time: 10–20 million (order of hundred million cycles for LC )
    - tolerance in thickness
 
 
other related website:
electrochromic layers
 
Electrochromic Devices (by DR. Sue A. Carter from Physics Department, ISB)
 
**Electrochromic Elecments(by X-RAY Absorption Spectroscopy Laboratory ISSP)

  Maximum Bleaching/Coloration Time      < 60 sec (usually about 10-20 sec)
  Working Potential from -2.4 V (coloration) to +1.5 V (bleaching)
  Working Temperature (tested) from 13 to 25 °C
  Working area about 50 mm x 50 mm
  Thickness < 10 mm

 
 
 
2. Conjugated Polymers for Electrochromism (project by Prof John R., Department of Chemistry, U of Florida)
 
Our group is interested in tuning available colors in electrochromic polymers through their repeat unit structure. By incorporating pendant groups onto the parent molecule, or introducing alternating electron donating and accepting units within the polymer repeat unit, we can adjust the electronic energy levels of the conjugated polymer. These monomers are then electrochemically polymerized into films that can switch from a highly colored state to either a transparent or a different colored state. ...
 
 * (Dual polymer lateral display composed of red/blue to transparent switching)
 
# Chemical repeat unit structures of some conjugated electrochromic polymers with colors corresponding to the doped (or oxidized) state (D), neutral state (N), and intermediate state (I).
 
 
1. various application take advantage of electrochromic material's fast switching time(how long ???), high optical contrast, wide color range(multiple change???)
2. * I don't really understand what this graph talks about. But it do look like my MATRIX.!!!
3. CHEMISTRY....
 
 
 Electrochromic Polymers(Conjugated polymers ) Department of Chemistry, U of Florida
 
* cant really understand this paper
 
 
 
 
 
 
 
3. Chameleon Material Can Switch Between Three Colors
# multiple color effect can be realized. When applying positive, neutral, and negative charge, the colour switch between green, blue, and pink.
*  the project is leading by professor Professor Eunkyoung Kim from organic polymer research group in the Department of Chemical Engineering at Yonsei University
 
 
 
 
 
4. Papers about EC application in smart Windows (not actually closely related to our project purpose, just take it as references)
A Dawning Day for Energy-Efficient Electrochromic Windows (science@berkeley lab )
 
WINDOWS OF THE FUTURE
comparision of PHOTOCHROMIC, THERMOCHROMIC, ELECTROCHROMIC, AND LC WINDOWS.
 
 
 
5. ALL ABOUT FUTURE
 
Siemens Electrochromic Display  (2005 - 2007)
* They applied a very thin layer of electrochromic material for displaying purpose, controlled by printed circuit and powered by think printable battery or a photovoltaic cell.
 
Electrochromic Display
*function simlilar as Elctronic Paper
 
Electrochromic Threads (2006)  Greg Sotzing, Chemistry Department, University of Connecticut
* With the idea of Chameleon Clothing, electrochromic threads were further developed.
 
 
 
6.Other Related Information
 
A Simple Magnet Can Control the Color of a Liquid, Making New Technologies Possible, department of Chemistry, UCR
 
They managed to control the color change of the small particls of iron oxide suspended in water, by adjusting the external magnetic field applied to the solution.
The discovery has potential to greatly improve the quality and size of electronic display screens and to enable the manufacture of products such as erasable and rewritable electronic paper and ink that can change color electromagnetically.
 
 
Thinking about our project? should we set big big goals? or should we be practical, see what we indeed can come out with?
but do we have the experiemental experience? we have no idea how to carry out chemical experiments.
WHAT CAN WE DO?? till the end of the 5th week, after searching for so many materials, we still do not have a clear direction.
 
 
 
FABCELL
* the LC ink project carried out at keio University
 
1. combine liquid crystal ink and conductive yarns woven into a sqare textile.
2. Applying voltage to the conductive yarn  -> change temperature -> change color of liquid crystal
3. control color by microcontrollers
4. function: a. flexible colour change.  b. shape reconstruction.
 
 
AJJER
* this is the only commercial group I could find about electrochromic material
 
 
 
 


 
Summary
 
Over the past 3 weeks, we have been looking closely into photochromic, thermochromic(LC and lecuodye), and finnally comes to electrochromic material.  For each material, we need to take in account their PROS and CONS, feasibility, changing parameters, and formal achievements.
 
After latest findings about electrochromic polymers, I ask myself these questions:
 
Is it possible to find a new electrochromic material that will switch between multiple colours and be able to be integrated with fabric????
YES it is possible:
Greg Sotzing of University of Connecticut invented threads of electrochromic polymers in 2006 and Professor Eunkyoung Kim from Yonsei University  are working on polymers changing colour among three different colours in three electrical states(positive, netrual, negtive). If this two technology were combined, such threads would be able to be woven to textile, that we would be easily control the change of T shirt could with different voltage applied.
 
Is it feasible for us to carry out this experiment???
 No. I really do not believe so. Both experiments mentioned above were carried out by experienced chemistry specialists.
However, we are not chemistry students. We do not have ANY BACKGROUND. what is more, there is no experimental station in our lab. And we do not have source for guildance in this field. No one are experienced how to carry out such experiments. We do not expect answer, but we need guildance.
 
Am I just disencouraging myself?
1. I fully understand, ideally, we are supposted to find out a NEW WEARABLE MATERIAL, that would appear multiple colours withunder human control. However, as I could intrerpret, a new material does not necessary mean a new polymer, a new kind of ink, or a new thread.
2. All the inventions and improvements related with electrochromic materials, are made by Chem or Material Specialists.
3. Just thinking about the FABCELL invented by KEIO univesity, they were still combining two current commercially available technology (Conductive Thread and Liquid Crystal Ink).  \
4. when it comes to our case, I still insist, that the feasible thing to do is to play magic with the current technologys. Most importantly, we NEED to use commercially available INK! otherwise, we will not even be able to apply it on textitle. Yes, I can think of making a thin thin layer of electrochromic display that would be convenient enough to wear or carry around. But how can we make the thin thin layer PROTOTYPE..
5. The problem now, comes that, the current colour changable inks are only changing between 2 colours. (That was also why I came out with the alternative way last week)
 
Question Remained:
WHAT SHOULD WE DO NEXT????
 
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