Know the Basics of Dispersing Nanosize Materials

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00:00:00 Dispersion and nanotechnology
00:01:51 Can I say anything new?
00:02:06 But….
00:03:11 Dispersion – have we moved forward?
00:03:47 Abstract
00:04:32 The Laws of Physics or The Crunch
00:05:40 The 4 S’s of nanotechnology
00:06:55 Bulk/Primary
00:07:45 Solid-solid diffusion
00:09:19 Important reference paper
00:10:06 Look how quickly coalescence occurs…
00:10:43 Inertial and van der Waals forces…..
00:12:14 Bridging will always occur - in the dry state!
00:12:50 Strength of adhesion – amended and original
00:13:45 Surface and size
00:15:13 Qualitative measure of dispersion efficiency
00:16:04 Agglomeration Factor, Fag - Agglomeration Number, FN
00:16:52 Surface – the 3 C’s
00:17:50 Surface sensitive techniques
00:18:56 Surface Composition/chemistry
00:20:40 TiO2 pigment
00:21:54 Bulk and surface composition
00:23:21 Surface atoms dominate as the size decreases
00:23:52 Nanoclusters
00:24:10 Chemisorption induced segregation
00:24:56 (Surface) charge
00:25:50 Producing a stable dispersion
00:29:50 Producing a stable dispersion
00:31:23 The beaker or vial test (charge stabilization)
00:32:52 Vial test with CeO2 polishing agent
00:34:12 Indications that there is a stability issue
00:35:04 The scientific (not empirical) route
00:37:00 Measurement with optimum conditions
00:37:12 Measurement with optimum conditions
00:37:37 Comparison between properly dispersed and poorly dispersed material
00:37:57 A few more words on stabilization
00:38:21 The +/- 30 mV stuff…
00:39:21 Stabilization – early literature
00:40:02 Steric stabilization
00:40:58 Powders are the problem!
00:41:48 Powders – after Adair
00:42:46 Adhesion forces - dry milling
00:43:23 More information in recent webinars
00:43:38 Useful paper
00:44:02 This leads to the comminution limit (CL)
00:44:23 Bottom up – not bottoms up….
00:45:34 Top down or bottom up?
00:46:11 Time for grinding/rate of grinding
00:46:29 Ultrafine (”Nano”) grinding
00:46:43 So we really need to do it in the wet…
00:47:18 Ball Mill – Fischer: Colloidal Dispersions
00:47:48 Colloid Mill
00:48:01 High energy input to break solids
00:48:31 And a lot of time….
00:48:50 Dissolution
00:49:26 Stress corrosion milling/cracking
00:49:47 Bottom up
00:50:25 Tests for ‘nano’
00:50:42 Settling rates – taken from ASTM E2490-09 (15)
00:51:09 Settling rates - comments
00:51:40 K. Eric Drexler
00:52:14 Question & Answers
00:55:27 Thank you for your 1 508 768 6434

'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


  • Alan Rawle Ph.D. - Principal Scientist Laser Diffraction

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Who should attend?
Anyone concerned with nanotechnology especially those new to dispersion of larger systems to nominally nanosystems (< 100 nm)

What will you learn?
The difficulties of making small dispersed materials from top-down processes and the general factors in achieving ‘good’ dispersion in systems