1. PMI EUROPE WORK SHOP Advances In Characterization Techniques Dr. Krishna Gupta Technical Director Porous Materials, Inc., USA

2. PMI EUROPE WORK SHOP Topics ê Accuracy and Reproducibility ê Technology for Characterization under Application Environment ê Directional Porometry ê Clamp-On Porometry ê Flexibility to Accommodate Samples of Wide Variety of Shapes, Sizes and Porosity ê Ease of Operation F Flow Porometry

3. PMI EUROPE WORK SHOP Topics ê Diffusion Gas Permeametry ê High Flow Gas Permeametry ê Microflow liquid permeametry ê High flow liquid permeametry at high temperature & high presure ê Envelope surface area, average particle size & average fiber diameter analysis ê Water vapor transmission rate F Permeametry

4. PMI EUROPE WORK SHOP Topics ê Stainless steel sample chamber ê Special design to minimize contact with mercury F Non-Mercury Intrusion Porosimetry ê Sample chamber that permits mercury intrusion porosimeter to be used as non-mercury intrusion porosimeter ê Water Intrusion Porosimeter F Mercury Intrusion Porosimetry

5. PMI EUROPE WORK SHOP Topics F Conclusions F Gas Adsorption

6. PMI EUROPE WORK SHOP Flow Porometry (Capillary Flow Porometry) F Design modified to minimized errors F Appropriate corrections incorporated Accuracy and Reproducibility F Most important sources of random & systematic errors identified

7. PMI EUROPE WORK SHOP Flow Porometry (Capillary Flow Porometry) Accuracy

8. PMI EUROPE WORK SHOP Flow Porometry (Capillary Flow Porometry) F Same operator F Same machine F Same wetting liquid F Same filter Repeatability F Bubble point repeated 32 times

9. PMI EUROPE WORK SHOP Flow Porometry (Capillary Flow Porometry) FilterWetting Liquid PorewickSilwick Sintered Stainless Steel1.8%1.2% Battery Separator0.2%1.5% Paper1.7%1.1%

10. PMI EUROPE WORK SHOP Flow Porometry (Capillary Flow Porometry) F Errors due to the use of different machines MachineBubble point pore diameter, Mean Value,  m Standard deviation Deviation from average of all machines 118.350.53%-1.34% 218.780.48%0.93% 318.372.34%0.28% 418.630.75%0.13%

11. PMI EUROPE WORK SHOP Flow Porometry (Capillary Flow Porometry) F Operator errors MachineAverage of mean,  m Difference between mean values by operators mm Percentages 118.380.0580.32% 218.770.0050.03% 318.770.2221.19% 418.730.2131.14%

12. PMI EUROPE WORK SHOP Technology for Characterization under Simulated Application Environment Compressive Stress F Arrangement for testing sample under compressive stress Arrangement for testing sample under compressive stress

13. PMI EUROPE WORK SHOP Technology for Characterization under Simulated Application Environment F Sample size as large as 8 inches F Programmed to apply desired stress, perform test & release stress Compressive Stress Features: F Any compressive stress up to 1000 psi (700 kPa)

14. PMI EUROPE WORK SHOP Technology for Characterization under Simulated Application Environment Effect of compressive stress on bubble point pore diameter

15. PMI EUROPE WORK SHOP Technology for Characterization under Simulated Application Environment

16. PMI EUROPE WORK SHOP Technology for Characterization under Simulated Application Environment Cyclic stress F Stress cycles are applied on sample sandwiched between two porous plates and the sample is tested during a pause in the stress cycle

17. PMI EUROPE WORK SHOP Technology for Characterization under Simulated Application Environment Sample chamber for cyclic compression porometer

18. PMI EUROPE WORK SHOP Technology for Characterization under Simulated Application Environment F Stress may be applied and released at fixed rates F Duration of cycle 10 s F Frequency adjustable by changing the duration of application of stress Features: F Any desired stress between 15 and 3000 psi

19. PMI EUROPE WORK SHOP Technology for Characterization under Simulated Application Environment F Programmed to interrupt after specified number of cycles, wait for a predetermined length of time, measure characteristics and then continue stressing Features:

20. PMI EUROPE WORK SHOP Technology for Characterization under Simulated Application Environment F Sample can be tested any required number of times within a specified range Features: F Fully automated

21. PMI EUROPE WORK SHOP Technology for Characterization under Simulated Application Environment Change of bubble point pore diameter with number of stress cycles

22. PMI EUROPE WORK SHOP Technology for Characterization under Simulated Application Environment Effects of Cyclic compression on permeability

23. PMI EUROPE WORK SHOP Technology for Characterization under Simulated Application Environment Aggressive environment Pore size of separator determined using KOH solution

24. PMI EUROPE WORK SHOP Technology for Characterization under Simulated Application Environment Directional Porometry F In this technique, Gas is allowed to displace liquid in pores in the specified direction

25. PMI EUROPE WORK SHOP Technology for Characterization under Simulated Application Environment Sample chamber for determination of in-plane (x-y plane) pore structure

26. PMI EUROPE WORK SHOP Technology for Characterization under Simulated Application Environment Sample chamber for determination of pore structure in a specific direction such as x or y

27. PMI EUROPE WORK SHOP Technology for Characterization under Simulated Application Environment Material Bubble point,  mMean flow pore diameter,  m Fuel cell component z-direction14.11.92 x-direction14.61.04 y-direction7.600.57 Printer Paper z-direction12.44.20 x-y plane1.110.09 Transmission fluid filter felt z-direction80.4― x-y plane43.3― Liquid filter z-direction34.5― x-y plane15.3―

28. PMI EUROPE WORK SHOP Clamp-On Porometry F Sample chamber clamps on any desired location of sample (No need to cut sample & damage the material) Typical chambers for clamp-on porometer

29. PMI EUROPE WORK SHOP Clamp-On Porometry F No damage to the bulk material F Test may be performed on any location in the bulk material Advantages: F Very fast

30. PMI EUROPE WORK SHOP Flexibility to Accommodate a Wide Variety of Sample Shape, Size and Porosity F Plates Shapes: F Sheets F Hollow Fibers F Pen tips F Discs F Cartridges F Rods F Diapers F Tubes F Odd shapes F Powders F Nanofibers

31. PMI EUROPE WORK SHOP Flexibility to Accommodate a Wide Variety of Sample Shape, Size and Porosity F 8 inch wafers F Two feet cartridges F Entire diaper Size: F Micron size biomedical devices

32. PMI EUROPE WORK SHOP Flexibility to Accommodate a Wide Variety of Sample Shape, Size and Porosity Materials: F Ceramics F Nonwovens F Metals F Composites F Textiles F Gels F Sponges F Hydrogels

33. PMI EUROPE WORK SHOP Ease of Operation F Fully automated ê Test execution ê Data storage ê Data Reduction F User friendly interface F Menu driven windows based software

34. PMI EUROPE WORK SHOP Ease of Operation F Graphical display of real time test status and results of test in progress F Many user specified formats for plotting & display of results F Minimal operator involvement

35. PMI EUROPE WORK SHOP Advanced Permeametry F Different directions; x, y and z directions, x-y plane F At elevated temperatures, high pressure & under stress F Very low or very high permeability Capability: F A wide variety of gases, liquids & strong chemicals

36. PMI EUROPE WORK SHOP Diffusion Gas Permeametry Principle of diffusion permeameter

37. PMI EUROPE WORK SHOP Diffusion Gas Permeameter The PMI Diffusion Permeameter

38. PMI EUROPE WORK SHOP Diffusion Gas Permeametry (dV s /dt) = (T s Vo/Tp s )(dp/dt) V s = gas flow in volume of gas at STP V o = volume of chamber on the outlet side Flow rate < 0.75x10 -4 cm 3 /s Change of outlet gas pressure with time for two samples measured in the PMI Diffusion Permeameter.

39. PMI EUROPE WORK SHOP High Flow Gas Permeametry F Can measure flow rates as high as 10 5 cm 3 /s F Can test large size components F Uses actual component; Diaper, Cartridges, etc.

40. PMI EUROPE WORK SHOP High Flow Gas Permeametry PMI High Flow Gas Permeameter

41. PMI EUROPE WORK SHOP Microflow Liquid Permeametry ê Ceramic discs ê Membranes ê Potatoes ê Other vegetables & fruit F Uses a microbalance to measure small weights of displaced liquid, 10 -4 cm 3 /s F Measures very low liquid permeability in materials

42. PMI EUROPE WORK SHOP High Flow Liquid Permeametry at High Temperatures and High Pressures F Measures high permeability of application fluids at high temperature through actual parts under compressive stress

43. PMI EUROPE WORK SHOP High Flow Liquid Permeametry at High Temperatures and High Pressures The PMI high pressure, high temperature and high flow liquid permeameter

44. PMI EUROPE WORK SHOP High Flow Liquid Permeametry at High Temperatures and High Pressures F Compressive stress on sample 300 psi F Liquid: Oil F Flow rate: 2 L/min Capability: F Temperature 100  C

45. PMI EUROPE WORK SHOP Envelope Surface Area, Average Particle Size & Average Fiber Diameter Measurement The PMI Envelope Surface Area, Average Fiber Diameter and Average Particle Size Analyzer

46. PMI EUROPE WORK SHOP Envelope Surface Area, Average Particle Size & Average Fiber Diameter Measurement Envelope Surface Area F Computes surface area from flow rate using Kozeny and Carman relation

47. PMI EUROPE WORK SHOP Envelope Surface Area, Average Particle Size & Average Fiber Diameter Measurement Envelope Surface Area  [Fl/pA] ={P 3 /[K(1-P) 2 S 2 m]}+[ZP 2 p]/[(1- P)S(2ppr) 1/2 ] F = gas flow rate in volume at average pressure, p l = thickness of sample per unit timep = pressure drop, (p i -p o ) p = average pressure, [(p i +p o )/2], where p i is the inletr b = bulk density of sample pressure and p o is the outlet pressurer a = true density of sample A = cross-sectional area of samplem = viscosity of gas P = porosity (pore volume/total volume) = [1-(rb/ra)] p = average pressure, [(p i +p o )/2], where p i is ther = density of the gas at inlet pressure and p o is the outlet pressure the average pressure, p S = through pore surface area per unit volumeZ = a constant. It is shown to of solid in the sample be (48/13p) K = a constant dependent on the geometry of the pores in the media. It has a value close to 5 for random pored media

48. PMI EUROPE WORK SHOP Envelope Surface Area, Average Particle Size & Average Fiber Diameter Measurement F Comparison between BET and ESA Methods Sample IDESA surface area (m^ 2 /g) BET surface area (m^ 2 /g) ESA particle size (microns) BET particle size (microns) Magnesium stearate A 11.1312.160.430.39 Magnesium stearate B 6.977.130.690.67 Glass bubbles A 0.890.91514.8214.83 Glass bubbles B 1.761.9122.2520.53

49. PMI EUROPE WORK SHOP Envelope Surface Area, Average Particle Size & Average Fiber Diameter Measurement d = the average particle size S = specific surface area of the sample (total Surface area/mass) r = true density of the material Average particle size F Computes from surface area assuming same size & spherical shape of particles d = 6 SrSr

50. PMI EUROPE WORK SHOP Envelope Surface Area, Average Particle Size & Average Fiber Diameter Measurement F Comparison between BET and ESA Methods Sample IDESA surface area (m^ 2 /g) BET surface area (m^ 2 /g) ESA particle size (microns) BET particle size (microns) Magnesium stearate A 11.1312.160.430.39 Magnesium stearate B 6.977.130.690.67 Glass bubbles A 0.890.91514.8214.83 Glass bubbles B 1.761.9122.2520.53

51. PMI EUROPE WORK SHOP Envelope Surface Area, Average Particle Size & Average Fiber Diameter Measurement  (4  pAR 2 )/(mFl) = 64 c 1.5 [1+52c 3 ] Average fiber diameter F Computed from flow rate using Davies equation P  0.7-0.99 c = packing density (ratio of volume of fibers to volume of sample) = (1-P)  p = pressure gradient A = cross-sectional area of sample R = average fiber radius  = viscosity of gas F = gas flow rate average pressure L = thickness of sample

52. PMI EUROPE WORK SHOP Envelope Surface Area, Average Particle Size & Average Fiber Diameter Measurement Measured fiber diameters in microns plotted against the actual fiber diameters

53. PMI EUROPE WORK SHOP Envelope Surface Area, Average Particle Size & Average Fiber Diameter Measurement F Average fiber diameter can also be computed from the envelope surface area. Assuming the fibers to have the same radius and the same length; D f = 4V/S = 4/Sr D f = average fiber diameter V = volume of fibers per unit mass S = envelope surface area of fibers per unit mass r = true density of fibers

54. PMI EUROPE WORK SHOP Water Vapor Transmission Transmission under pressure gradient Principle of Water vapor transmission analyzer

55. PMI EUROPE WORK SHOP Water Vapor Transmission Transmission under pressure gradient Change of pressure on the outlet side of two samples of the naphion membrane in the PMI Water Vapor Transmission Analyzer

56. PMI EUROPE WORK SHOP Water Vapor Transmission Transmission under concentration gradient Line diagram showing the operating principle of PMI Advanced Water Vapor Transmission Analyzer

57. PMI EUROPE WORK SHOP Water Vapor Transmission Transmission under concentration gradient Water vapor transmission rate through several samples

58. PMI EUROPE WORK SHOP Mercury Intrusion Porosimetry Stainless Steel Sample Chamber Stainless Steel Sample Chamber of The PMI Mercury Intrusion Porosimeter

59. PMI EUROPE WORK SHOP Mercury Intrusion Porosimetry Special design to minimize contact with mercury The PMI Mercury Intrusion Porosimeter

60. PMI EUROPE WORK SHOP Mercury Intrusion Porosimetry F Sample chamber is evacuated and pressurized without transferring the chamber and contacting mercury F Automatic cleaning of the system by evacuation F Separation of high-pressure section from low-pressure section

61. PMI EUROPE WORK SHOP Mercury Intrusion Porosimetry F Automatic drainage of mercury F In-situ pretreatment of the sample F Fully automated operation F Automatic refilling of penetrometer by mercury

62. PMI EUROPE WORK SHOP Non-Mercury Intrusion Prosimetry Sample Chamber That permits Mercury Intrusion Porosimeter to be used as a Non-Mercury Intrusion Porosimeter Sample Chamber for use to perform non-mercury intrusion tests in the PMI Mercury Intrusion Porosimeter

63. PMI EUROPE WORK SHOP Water Intrusion Porosimeter (Aquapore) F Water used as intrusion liquid F Can test hydrophobic materials F Can detect hydrophobic pores in a mixture F Uses absolutely no mercury

64. PMI EUROPE WORK SHOP Water Intrusion Porosimeter (Aquapore) The PMI Aquapore

65. PMI EUROPE WORK SHOP Gas Adsorption F Capable of very fast measurement (<10 min) of single point and multi- point surface areas F The PMI QBET for fast surface area measurement F A new technique developed by PMI

66. PMI EUROPE WORK SHOP Conclusions F Recent advances made in the technology of measurement and novel methods of measurement of properties using porometry, permeametry, porosimetry and gas adsorption have been discussed

67. PMI EUROPE WORK SHOP Conclusions F Results have been presented to show the improvements in accuracy and repeatability of results and ease of operation of the test.

68. PMI EUROPE WORK SHOP Conclusions ê compressive stress ê cyclic compression ê aggressive conditions ê elevated temperatures ê high pressures have been illustrated with examples F Measurement of characteristics under application environments involving:

69. PMI EUROPE WORK SHOP Thank You