Fecha registrada: May 28 2019

Duration: 56 minutes 12 seconds

'Nano’ is all about small. A dispersed system is smaller than its agglomerated or aggregated precursor. The fundamental physical principles outlining dispersion in small systems will be discussed. This should act as a primer to those interested in making stable systems < 100 nm

Table of contents
1. Dispersion and nanotechnology
01:51
2. Can I say anything new?
00:15
3. But….
01:05
4. Dispersion – have we moved forward?
00:36
5. Abstract
00:45
6. The Laws of Physics or The Crunch
01:08
7. The 4 S’s of nanotechnology
01:15
8. Bulk/Primary
00:50
9. Solid-solid diffusion
01:34
10. Important reference paper
00:47
11. Look how quickly coalescence occurs…
00:37
12. Inertial and van der Waals forces…..
01:31
13. Bridging will always occur - in the dry state!
00:36
14. Strength of adhesion – amended and original
00:55
15. Surface and size
01:28
16. Qualitative measure of dispersion efficiency
00:51
17. Agglomeration Factor, Fag - Agglomeration Number, FN
00:48
18. Surface – the 3 C’s
00:58
19. Surface sensitive techniques
01:06
20. Surface Composition/chemistry
01:44
21. TiO2 pigment
01:14
22. Bulk and surface composition
01:27
23. Surface atoms dominate as the size decreases
00:31
24. Nanoclusters
00:18
25. Chemisorption induced segregation
00:46
26. (Surface) charge
00:54
27. Producing a stable dispersion
04:00
28. Producing a stable dispersion
01:33
29. The beaker or vial test (charge stabilization)
01:29
30. Vial test with CeO2 polishing agent
01:20
31. Indications that there is a stability issue
00:52
32. The scientific (not empirical) route
01:56
33. Measurement with optimum conditions
00:12
34. Measurement with optimum conditions
00:25
35. Comparison between properly dispersed and poorly dispersed material
00:20
36. A few more words on stabilization
00:24
37. The +/- 30 mV stuff…
01:00
38. Stabilization – early literature
00:41
39. Steric stabilization
00:56
40. Powders are the problem!
00:50
41. Powders – after Adair
00:58
42. Adhesion forces - dry milling
00:37
43. More information in recent webinars
00:15
44. Useful paper
00:24
45. This leads to the comminution limit (CL)
00:21
46. Bottom up – not bottoms up….
01:11
47. Top down or bottom up?
00:37
48. Time for grinding/rate of grinding
00:18
49. Ultrafine (”Nano”) grinding
00:14
50. So we really need to do it in the wet…
00:35
51. Ball Mill – Fischer: Colloidal Dispersions
00:30
52. Colloid Mill
00:13
53. High energy input to break solids
00:30
54. And a lot of time….
00:19
55. Dissolution
00:36
56. Stress corrosion milling/cracking
00:21
57. Bottom up
00:38
58. Tests for ‘nano’
00:17
59. Settling rates – taken from ASTM E2490-09 (15)
00:27
60. Settling rates - comments
00:31
61. K. Eric Drexler
00:34
62. Question & Answers
03:13
63. Thank you for your attentionalan.rawle@malvernpanalytical.com+ 1 508 768 6434
00:45