Conduction Mechanism in Polyaniline Author Alips Srivastava Mentor Prof. A.Q. Contractor

Objectives: After interacting with this Learning object; you will be able to: 1.Identify the formation of a polaron 1.Identify the formation of a bipolaron 1.Explain the steps in conduction mechanism of Polyaniline

Master layout or diagram Make a schematic diagram of the concept Explain the animator about the beginning and ending of the process. Draw image big enough for explaining. In above image, identify and label different components of the process/phenomenon. (These are like characters in a film)‏ Illustrate the basic flow of action by using arrows. Use BOLD lines in the diagram, (minimum 2pts.)‏ In the slide after that, provide the definitions of ALL the labels used in the diagram INSTRUCTIONS SLIDE

Master Layout STEP 1: Oxidation - e - + e - Leucoemeraldine base Formation of Polaron Fig 1 A B

Master Layout Fig 2 Formation of Polaron Two possibilities on further oxidation Formation of two PolaronsFormation of Bipolarons B 1. B 2. T1 T2

Master Layout e - + e - Fig 3 B C Step 2: Possibility 1: Formation of two Polarons (further oxidation of Polaron)‏ Polaron Two Polaron

Master Layout STEP 2 - e - + e - Step 2 : Possibility 2: Formation of Bipolaron (further oxidation of Polaron)‏ Fig 4 B E Polaron Bipolaron

Master Layout 5 1 STEP 3 Bipolaron Fig 4 a. b. c. d. e.

Definitions of the components: Polyaniline: Polyaniline is an electronically conducting polymer, its intrinsic conductivity being attributed to its conjugated structure. Polaron: Polaron is a radical ion (spin ½) associated with a lattice distortion. Bipolaron: Bipolaron is a pair of like charges (here, a dication) associated with a strong local lattice distortion.

Explain the process In this step, use an example to explain the concept. It can be an analogy, a scenario, or an action which explains this concept/process/topic Try to use examples from day-to-day life to make it more clear You have to describe what steps the animator should take to make your concept come alive as a series of moving images. Keep the examples simple to understand, and also to illustrate/animate.

Analogy / Scenario / Action

Stepwise description of process The goal of the IDD is to provide instructions to an animator who is not a expert. You have to describe what steps the animator should take to make your concept come alive as a moving visualization. Use one slide per step. This will ensure clarity of the explanation. Add a image of the step in the box, and the details in the table below the box. You can use any images for reference, but mention about it's copyright status The animator will have to re-draw / re-create the drawings Add more slides as per the requirement of the animation

Step 1: Fig 1 Leucoemeraldine base form of polyaniline upon removal of one electron, by chemical or electrochemical means, results in generation of polaron 1. Make all the black dots on the diagram clickable. 2. Once one black dot is clicked show it leaving the N and fading away. 3. Then show the diagram. 4. show the two way arrow with electron ‘–e’ and ‘+e’. Click on any one electron on the polymer backbone to generate Polaron Audio Narration / Text to be displayed Description of the action/ Instructions for the animator Instruction for the users/Action A B

Step 2: Fig 2 First T1 text appears then T2 and the arrows. Then B1 and B2 options appear which are clickable If B1 is clicked then show step No 3 If B2 is clicked then show step no 4 Click on any one of the possibility Audio Narration / Text to be displayed Description of the action/ Instructions for the animator Instruction for the users/Action

Step 3: Fig 3 1. “Formation of two polarons is prohibited because it is an energetically unfavourable process.” 1. Make all the black dots above N on the diagram clickable except the second N. 2. Once one black dot is clicked show it leaving the N and fading away. 3. Then show the diagram. 4. show the two way arrow with electron ‘–e’ and ‘+e’. 5. Dialogue box appears with text 1. Possibility 1: Click on another electron on any other nitrogen atom to further oxidize the Polaron Audio Narration / Text to be displayed Description of the action/ Instructions for the animator Instruction for the users/Action B C

Step 4: Fig 4 1. “Further oxidation, i.e. removal of a second electron, results in formation of a bipolaron, which is energetically more favourable than formation of two polarons” 1. Make the black dot above the second N on the diagram clickable. 2. Once the black dot is clicked show it leaving the N and fading away. 3. Then show the diagram. 4. show the two way arrow with electron ‘–e’ and ‘+e’. 5. Dialogue box appears with text 1. Possibility 1: Click on another electron on same nitrogen atom to further oxidize the Polaron Audio Narration / Text to be displayed Description of the action/ Instructions for the animator Instruction for the users/Action B E

Step 3: Fig 4  These are all the "Resonance Structures" of bipolaron.  Electrons/holes (positive charges) move along the backbone is because the backbone is conjugated, i.e., having an arrangement of alternate single and double bonds with intermittent non-bonded nitrogen electrons. Because of this arrangement, electrons/holes can easily travel along the backbone resulting in the formation of resonance structures, all of which have equal energy.  Resonance structures imply that at a given moment bipolaron can exist as any of the indicated structures since all of them are equal in energy. Fig a. appears Fig b. appears with action text 1. with electron moving as shown by the arrow. Fig c. appears to show the result of shift in electron. Fig d. next show an electron from the last compound moving as shown by the arrow to the second compound Fig e. appears to show result of shift in electron. 1. Click on the third compound of bipolaron to see the separation of the positive charges and conduction along the polyaniline backbone. Audio Narration / Text to be displayed Description of the action/ Instructions for the animator Instruction for the users/Action

Animation design Please see the design template provided in the next slide. This is a sample template, and you are free to change as per your design requirements. Try and recreate the sections/subsections as shown in the template

Want to know more… (Further Reading) ‏ Definitions Formula with derivation (if any) ‏ Graphs/Diagram (for reference) ‏ Animation Area Test your understanding (questionnaire) ‏ Lets Learn! Concepts Assumptions (if any) ‏ Lets Sum up (summary) ‏ Instructions/ Working area Suggestions Did you know? (entry behaviour) ‏ Keywords Radio buttons (if any) ‏ Drop down (if any) ‏ Value inputs (if any) ‏ EnterPlay/pauseRestart Feedback below the animation What will you learn Summative evaluation If any of them are not mentioned in the IDD deleted

Interactivity and Boundary limits In this section, you will add the ‘Interactivity’ options to the animation. Use the template in the next slide to give the details. Insert the image of the step/s (explained earlier in the Section 3) in the box, and provide the details in the table below. The details of Interactivity could be: Types: Drop down, Slider bar, Data inputs etc. Options: Select one, Multiple selections etc Boundary Limits: Values of the parameters, which won’t show results after a particular point Results: Explain the effect of the interaction in this column Add more slides if necessary

INSTRUCTIONS SLIDE Questionnaire to test the user A small, (5 questions) questionnaire can be created in the next slide, to test the user's comprehension. This can be an objective type questionnaire. It can also be an exercise, based on the concept taught in this animation. Please give the answer key also.

Questionnaire 1. Polyaniline is an Answers: a) electronically conducting polymer b) ionically conducting polymer c)‏ none of these 2. Conducting species in polyaniline is Answers: a) Polaron b) Bipolaron c) Either of them d)‏ Both of them 3. Polyaniline is conducting due to Answers: a) its conjugated structure b) its ability to form radical ions c) both of the above reasons d)‏ neither of the above reasons

Links for further reading J.L. Bredas, and G.B. Street, Acc. Chem. Res. 18, 309 (1985). B. Sari, A. Gok, and D. Sahin J. Appl. Polym. Sci. 101, 241 (2006). M. Kaneko, and K. Kaneto Reac Func. Polym. 37, 155 (1998). C. Aleman, C.A. Ferreira, J. Torras, A. Meneguzzi, M. Canales, M.A.S. Rodrigues, and J. Casanovas Polymer doi: /j.polymer

Summary: Polyaniline is an electronically conducting polymer Polyaniline’s intrinsic conductivity being attributed to its conjugated structure. 3. Polaron is a radical ion (spin ½) associated with a lattice distortion. 4. Bipolaron is a pair of like charges (here, a dication) associated with a strong local lattice distortion.