Difference between revisions of "Assembly of large-area, highly ordered, crack-free inverse opal films"

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== Overview ==
 
== Overview ==
A new synthesis of crack-free inverse opal films over large scales (cm) is presented. The two step process consists a) of an evaporation of polymeric colloids in a hydrolyzed silicate sol-gel precursor solution and b) a colloidal/matrix coassembly. The synthesis of multilayered hierarchical films are also demonstrated. Furthermore, the inverse opal films were converted to inverse opal films of other materials as porous Si and <math>TiO_2</math> while maintaining their morphology during the gas solid displacement reaction.
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A new synthesis of crack-free inverse opal films over cm length scales is presented. The two step process consists of a) an evaporative deposition of polymeric colloids in a hydrolyzed silicate sol-gel precursor solution and b) a colloidal/matrix coassembly. The preferential grwoth direction is <110>. The synthesis of multilayered hierarchical films are also demonstrated. Furthermore, the inverse opal films were converted to inverse opal films of other materials as porous Si and <math>TiO_2</math> while maintaining their morphology during the gas/solid displacement reaction.
 
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for assembling highly ordered,
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crack-free inverse opal films over a centimeter scale. Multilayered
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composite colloidal crystal films have been generated via evaporative
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deposition of polymeric colloidal spheres suspended within a
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hydrolyzed silicate sol-gel precursor solution. The coassembly of a
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sacrificial colloidal template with a matrix material avoids the need
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for liquid infiltration into the preassembled colloidal crystal and
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minimizes the associated cracking and inhomogeneities of the resulting
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inverse opal films.
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preferential growth along the <110> direction and
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unusual fracture behavior. We demonstrate that this coassembly
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approach allows the fabrication of hierarchical structures not
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achievable by conventional methods, such as multilayered films
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and deposition onto patterned or curved surfaces.
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== Results and Discussion ==
 
== Results and Discussion ==
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Cracking seems to occur along {111} planes for thin films, which is consistent with conventional evaporative deposited films,  whereas thicker films seem to crack along {110} planes. 
  
 
[[Image:Hatton2010 4.png|300px|thumb|right|caption]]
 
[[Image:Hatton2010 4.png|300px|thumb|right|caption]]

Revision as of 02:12, 13 September 2010

Birgit Hausmann

Reference

B. Hatton et. al. "Assembly of large-area, highly ordered, crack-free inverse opal films" PNAS 107 (23) 2010

Keywords

Coassembly, colloidal assembly, crack-free films, inverse opals, nanoporous

Overview

A new synthesis of crack-free inverse opal films over cm length scales is presented. The two step process consists of a) an evaporative deposition of polymeric colloids in a hydrolyzed silicate sol-gel precursor solution and b) a colloidal/matrix coassembly. The preferential grwoth direction is <110>. The synthesis of multilayered hierarchical films are also demonstrated. Furthermore, the inverse opal films were converted to inverse opal films of other materials as porous Si and <math>TiO_2</math> while maintaining their morphology during the gas/solid displacement reaction.

Results and Discussion

Cracking seems to occur along {111} planes for thin films, which is consistent with conventional evaporative deposited films, whereas thicker films seem to crack along {110} planes.

caption