Negative replicas

Fig. 3. Shadows cast by simple solidprofiles. It can be seen that the shadows cast in positive and negative replicas are not interchangeable in either shape or tone. (From ref. [54] with permission.)...

CVD, and electrodeposition, depending on the desired composition. Removal of the colloidal templating spheres renders a negative replica (the inverse opal) structure of the active material, with an interconnected, 3-D array of pores, typically sized in the hundreds of nanometers. 

Highly ordered mesoporous silica can be regenerated from a mesoporous carbon CMK-3 that is a negative replica of mesoporous silica SBA-15, indicating reversible replication between carbon and inorganic materials.[193] The advantage of this synthesis method is that it does not need to make the same silica material (template). This method is likely to be a valuable complement to the existing methods for the fabrication of new mesoporous silicas and other composition materials. 

CMK-8 is a rod-type m oporous carbon that is a faithful negative replica of a mesoporous silica of cubic symmetry used as template. One of the advanta s of the synthetic method used for this material is that it affords easy tunability of pore sizes from 4 to 12 nm via simple hydrothermal treatment [93]. CMK-8 was obtained using sucrose as carbon... 

The obtained carbon monolith is a positive replica of the silica monolith on the micrometre scale, and a negative replica on the... 

After that, the PDMS negative replica was exposed to 2 min air plasma (RF level high, 0.1 Torr, PDC-32G, Harrick Plasma, USA) and functionalized with a layer of fluorosilanes. Again, a 10 1 mixture of PDMS was cast and cured overnight at 70 °C to yield a positive replica of the master. Contact angles were measitred on the bare PDMS positive and on its surface following subsequent functionalization with fluorosilanes. 

Fig. 14. Scaffold fabrication using rapid prototyped negative replica (a) A computergenerated 3-D negative replica of a scaffold with a cubical pore shape (b) the negative replica of the scaffold fabricated using a rapid prototyping machine (c) the polymer scaffold fabricated using the negative replica (d) SEM micrograph of the internal pore structure of the generated scaffold (V. J. Chen and P. X. Ma, unpublished data, 2003).

Drop a low viscosity embedding resin, such as Epotek 301 (Epoxy Technology Inc., Billerica, MA) into the molded silicone (negative) replica. Turn the mold over onto an SEM stub and allow to cure overnight. 

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