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Swelling of polymer network

Swelling of polymer network. Polymer network absorbs large amount of solvent causing a significant increase in the volume of polymer network. This phenomena is called swelling. swelling. Related LOs: > Prior V iewing – Crosslinking – 3 dimensional network formation, Polyelectrolytes

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Swelling of polymer network

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  1. Swelling of polymer network Polymer network absorbs large amount of solvent causing a significant increase in the volume of polymer network. This phenomena is called swelling. swelling • Related LOs: • > Prior Viewing – Crosslinking – 3 dimensional network formation, Polyelectrolytes > Future Viewing – • Course Name: Introduction to macromolecules Level: PG • Author: SunilkumarKhandavalli, Project Associate, IIT Madras • Mentor: Dr. Abhijit P Deshpande, Department of Chemical Engineering

  2. Learning objectives 1 After interacting with this Learning Object, the learner will be able to: • Estimate the degree of swelling • Estimate the crosslink density • Derive relationship between swelling and network elasticity using theories 2 3 4 5

  3. General Instructions to the animator • Click on slide show of each Main layout slide to preview the animation: • Each object is numbered according to the order of animation (as shown in slide show). • Only the sequence of animation of object is given in slide show, but the point of time at which the object has to animated, between audio narration/before/after is mentioned in the instruction to animator section and audio narration section. An example is shown below. Audio narration: As we can see (1) the object is a rectangle. The figure labeled (1) should be animated between the blue text (audio narration). • All the figures should be redrawn neatly • An instruction to the animator is given on some images such as above on a rectangle • Colors of figures presented have no significance, a good combination of colors for better presentation may also be chosen based on your imagination. • Text in red is an instruction to the animator 1 Instruction to the animator

  4. Swelling Definition Master Layout1 Swelling of polymer network

  5. Introduction to Swelling Master Layout1 - step1 This animation consists of 4 parts: Part 1 – Swelling Definition Part 2– Swelling Mechanism • Part 3 – Swelling in polyelectrolytes • Part 4 – Swelling-Elasticity relationship 1 polymer network 0 0 2 2 1 3 3 2 solvent 4 4 3 4 swelling 5 5

  6. Master Layout1 – step2 This animation consists of 4 parts: Part 1 – Swelling Definition Part 2– Swelling Mechanism • Part 3 – Swelling in polyelectrolytes • Part 4 – Swelling-Elasticity relationship 1 Drug delivery 1 Pharmaceutics Applications 3 2 2 0 Tissue engineering 3 3 2 4 4 0 swelling 5 5

  7. Master Layout2 – Step 1 Swelling Mechanism Swelling mechanism

  8. Master Layout2 – Step 1 Swelling mechanism 1 1 1 relaxed state This animation consists of 4 parts: Part 1 – Swelling Definition Part 2– Swelling Mechanism • Part 3 – Swelling in polyelectrolytes • Part 4 – Swelling-Elasticity relationship Small distance between crosslink points 2 2 0 3 3 2 4 4 5 5

  9. Master Layout2 – Step 2 Swelling Mechanism 0 4 1 1 solvent molecules 2 1 3 1 5 Δ∏os

  10. Master Layout2 – Step 3 Swelling Mechanism 91 1 5 4 31 6 7 91 Swellingpressure Elasticity 81 2 2 3 Equilibrium swelling 9 10 Wd = Mass of dry polymer Ws = Mass of swollen polymer

  11. Master Layout3 Swelling in polyelectrolytes Swelling in polyelectrolytes

  12. Master Layout3 – Step 1 Swelling in Polyelectrolytes 1s 1 0s This animation consists of 4 parts: Part 1 – Swelling Definition Part 2– Swelling Mechanism • Part 3 – Swelling in polyelectrolytes • Part 4 – Swelling-Elasticity relationship 2s Polyelectrolytes Charges 2 2 3 3 4 4 5 5

  13. Master Layout3 – Step 2 Swelling in polyelectrolytes 0 0

  14. 1 3 driving force = Δ∏os+Δ∏ion 2 2

  15. Master Layout3 – Step 4 Swelling in Polyelectrolytes 5 Please fill the figure with the white circles completely

  16. Swelling and Elasticity Relationship Master Layout4 1 Elasticity Relationship 2 2 3 3 swelling 4 4 SWELLING-ELASTICITY RELATIONSHIP 5 5

  17. Master Layout4 – Step 1 Swelling and Elasticity Relationship 1 This animation consists of 4 parts: Part 1 – Swelling Definition Part 2– Swelling Mechanism • Part 3 – Swelling in polyelectrolytes • Part 4 – Swelling-Elasticity relationship 1 Network parameters 2 0 1 2 1 1 Crosslink density (ρc) 3 swelling 0 4 5 5

  18. Master Layout4 – Step 2 1 2 2 0 0 1 Crosslink density 0 Degree of swelling 0

  19. Master Layout4 – Step 3 2 0 less free volume more free volume 3 1 1 3

  20. Master Layout4 – Step 4 1 0 1 0 2 swelling crosslink density (ρc) Flory-Rehner Theory 3 V2 = polymer volume fraction = 1/(1 + DS x ρp) DS = degree of swelling ρp = polymer density X = Flory Huggins parameter V1 = specific volume of polymer

  21. Master Layout4 – Step 5 0 1 1 Elasticity 0 crosslink density (ρc) 2 Rubber Elasticity Theory 3 E = ρcRT ρc = crosslink density R = gas constant T = temperature

  22. Master Layout4 – Step 6 6 Elasticity Network parameters 2 1 2 1 4 0 4 Rubber Elasticity Theory Flory-Rehner Theory swelling 0 2 2 crosslink density (ρc) 5

  23. Button 01 Button 02 Button 03 Slide 4 Slide 10 Slide 21 Slide 15 Swelling Swelling mechanism Swelling in polyelectrolytes Swelling-Elasticity Relationship Name of the section/stage Animation area Interactivity area Instructions/ Working area Credits

  24. APPENDIX 1 Questionnaire: • Given the weight of dry polymer network Wd = 0.68 g and weight of swollen polymer network, Ws = 1.2 g, estimate the degree of swelling • Polymer network A and B have the crosslink density values 0.1mmol/g and 0.25 mmol/g respectively. Then, the degree of swelling • a) A>B b) A < B c) A = B • 3. The crosslink density of a neutral polymer network (N) and a polyelectrolyte (P) is same. Then the degree of swelling • a) N = P b) N > P c) N< P

  25. Answers are highlighted in red: • Given the weight of dry polymer network Wd = 0.68 g and weight of swollen polymer network, Ws = 1.2 g, estimate the degree of swelling • Ans. 76 • Polymer network A and B have the crosslink density values 0.1mmol/g and 0.25 mmol/g respectively. Then, the degree of swelling • a) A < B b) A > B c) A = B • 3. If the a neutral polymer network (N) and a polyelectrolyte (P) have the same crosslink density. Then the degree of swelling values of N and P are: • a) N = P b) N > P c) N< P

  26. APPENDIX 2 Links for further reading • Books for basic concepts: • de Gennes, P. G. Scaling Concepts in Polymer Physics; Cornell University Press: Ithaca, 1979. • Dosek and Kuchanov, Polymer Networks, pp 79-98, VSP, 1992. • Treloar, L. R. G. The Physics of Rubber Elasticity, Oxford University Press, New York, 1975. Keywords: polymer network, crosslinks, solvent, intereaction

  27. APPENDIX 3 Summary • Polymer network when immersed in a solvent, it absorbs large amount of water, this phenomena is called swelling. • Swelling depends on the network parameters such as crosslink density. • Crosslink density can be estimated from swelling measurements using Flory-Rehner theory. • A relationship between swelling and elasticity can be established using the theory of rubber elasticity. • Polyelectrolytes swell enormously due to the presence of charged groups. • Swelling phenomena has many applications such as pharmaceuticals, tissue engineering and biomedicine.

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