Opening the Nano-​​World

A Defense Tech reader sent this inter­est­ing arti­cle my way. But, to be hon­est, Im not sure what to make of it.

I know a lit­tle bit about nan­otech­nol­ogy but not nec­es­sar­ily enough to really know if this devel­op­ment is sig­nif­i­cant. But I thought Id pass it along because DT read­ers may be able to enlighten me and oth­ers on this.

What appli­ca­tions in defense and intel­li­gence might this have? The arti­cle men­tions research fund­ing was pro­vided by the Army. From what I under­stand this sol-​​gel ink solu­tion is a process that could lead to the con­struc­tion of var­i­ous nano-​​structures such as lenses, optics and even fine structures.

Heres the arti­cle:

New sol-​​gel inks devel­oped by researchers at the University of Illinois can be printed into pat­terns to pro­duce three-​​dimensional struc­tures of metal oxides with nanoscale features.

The abil­ity to directly pat­tern func­tional oxides at the nanoscale opens a new avenue to func­tional devices. Potential appli­ca­tions include micro-​​fuel cells, pho­tonic crys­tals and gas sensors.

The researchers describe the new inks in a paper accepted for pub­li­ca­tion in the jour­nal Advanced Materials, and fea­tured on its Advances in Advance Web site.

Using this new fam­ily of inks, we have pro­duced fea­tures as small as 225 nanome­ters, said co-​​author Jennifer Lewis, the Thurnauer Professor of Materials Science and Engineering and direc­tor of the uni­ver­si­tys Frederick Seitz Materials Research Laboratory (FSMRL). Our goal is to get down to 100 nanome­ter fea­ture sizes.

To cre­ate three-​​dimensional struc­tures, the researchers use a robotic depo­si­tion process called direct-​​write assem­bly. The con­cen­trated sol-​​gel ink is dis­pensed as a fil­a­ment from a noz­zle approx­i­mately 1 micron in diam­e­ter (about 100 times smaller than a human hair). The ink is dis­pensed while a computer-​​controlled microp­o­si­tioner pre­cisely directs the path. After the pat­tern for the first layer is com­plete, the noz­zle is raised and another layer is deposited. This process is repeated until the desired shape is produced.

We have opened direct ink writ­ing to a new realm of func­tional mate­ri­als, said grad­u­ate stu­dent Eric Duoss, the papers lead author. Since we print the desired func­tion­al­ity directly, the need for com­pli­cated tem­plat­ing and repli­cat­ing schemes is eliminated.

Unlike pre­vi­ous inks, which require a liq­uid coag­u­la­tion reser­voir, the newly for­mu­lated inks are con­cen­trated enough to rapidly solid­ify and main­tain their shape in air, even as they span gaps in under­ly­ing layers.

This gives us the abil­ity to start, stop and repo­si­tion the flow of ink repeat­edly, pro­vid­ing exquis­ite con­trol over the depo­si­tion process, Duoss said. For exam­ple, we can directly pat­tern defects in three-​​dimensional struc­tures for use as pho­tonic crystals.

After the struc­tures have been assem­bled, they are con­verted to the desired func­tional oxide phase by heat­ing at ele­vated tem­per­a­ture. Titanium diox­ide, which pos­sesses high refrac­tive index and inter­est­ing elec­tri­cal prop­er­ties, is one mate­r­ial the researchers have suc­cess­fully produced.

The researchers ink design and pat­tern­ing approach can be read­ily extended to other materials.

There are a nearly end­less vari­ety of mate­ri­als to choose from, Lewis said. We envi­sion hav­ing a tool­box of inks that can print at the micro– and nanoscale. These inks will be used for het­ero­ge­neous inte­gra­tion with other man­u­fac­tur­ing tech­niques to cre­ate com­plex, func­tional devices com­posed of many dif­fer­ent materials.

In addi­tion to Lewis and Duoss, for­mer post-​​doctoral researcher Mariusz Twardowski is a co-​​author of the paper. 

(Gouge: BD)

– Christian

October 18th, 2007 | Roll Your Own | 26059 Comments »http://defensetech.org/2007/10/18/opening-the-nano-world/Opening+the+Nano-World2007-10-18+13%3A38%3A24Ward You can skip to the end and leave a response. Pinging is currently not allowed.