-- [ From: Garber, Charles A. * EMC.Ver #3.1 ] -- Mark Tobin wrote: ============================================ Has anybody heard of a material called Collodion being used for mounting materials for microscopy? I was asked by a colleague today and have not heard of it. Any information, UK suppliers in particular, would be greatly appreciated == ========================================== Collodion is manufactured by nitrating with nitric acid and sulfating with sulfuric acid relatively ordinary cotton to make it soluble (as a result of the addition of soluble nitrate and sulfate groups). When dried, the solids become what is known as "gun cotton" because of its use as gun powder . We believe that Parlodion is very similar but it does have a different corporate and process origin and it unlikely to be exactly identical. At the very least, one could expect that the degree of nitrating and sulfating might vary between the several different manufacturers, thereby resulting in at least some subtle variation in the final properties. This could of course help explain why one researcher might have difficulty repeating someone else's work. However, most researchers report obtaining similar results, whether the application is for the casting of a film for TEM grids or for the making of replicas on metallurgical or ceramic types of surfaces. We believe Collodion to be similar but not necessarily identical to the products called "Celloidin" and also, "LVN" , or "low viscosity nitrocellulose". And all of the mentioned products are supposed to be less explosive than the original "gun cotton". These materials, e.g. all of the above mentioned products based on nitrocellulose nitrate, at one time, were also used widely as embedding resins, but have been replaced in most applications by more modern materials. However, for the embedding of really large samples, a technique called "double embedding" still requires a nitrocellulose type material. However, for specific kinds of samples, there might be a preference for one or the other of the nitrocellulose based materials. Collodion, as well as the sister nitrocellulose based materials are flammable solids and require great care in their handling. Disclaimer: SPI has offered both Parlodion and Collodion in both solid form as well as in solutions of 2% in amyl acetate for a long time. Both the solid material or solutions can be ordered either directly from SPI in the USA or from our distributor in the UK listed on our website. Our interest is to make sure that people understand that generically, these materials seem to be similar and while it is to the first approximation, if you have one "in hand", then you already have something that is very close to the other. Our other interest is to remind everyone that these are trade names of manufacturing companies and first use on a page should include the use of a "TM". Chuck =================================================== Charles A. Garber, Ph. D. Ph: 1-(610)-436-5400 President 1-(800)-2424-SPI SPI SUPPLIES FAX: 1-(610)-436-5755 PO BOX 656 e-mail: [log in to unmask] West Chester, PA 19381-0656 USA Cust. Service: [log in to unmask] Look for us! ############################ WWW: http://www.2spi.com ############################ ==================================================