This reminds me of a discussion I heard on talk radio (Dr. Dean Edel) one night. He was talking about how "whoever it was" determined how high of intensity and for how long it takes to do damage to the retina. Apparently, they used patients who had been diagnosed with eye cancer and were scheduled to have one of their eyes removed. It gave them the perfect opportunity to blast an eye and then take it out to have a look.
It could be due to NSF/DOE/NIH/... dumping a ton of cash into the big Nanotech Initiative. Anyone who had the right combination of buzzwords in their proposal got funded.
Looking at the holes in the fiber that they show in the pictures (with a scale), each hole is about 5 microns in diameter. I would highly doubt that water would completely fill these holes.
The water pressure at whatever depth they were set at could probably determine how far in each hole the water may have been forced. They could simply cut the line well beyond that and splice in a new fiber. Of course, I assume that they would have to do this in an environment free of water.
Okay, maybe this is a stupid question, but what keeps the molecule from "bending back" on itself and re-attaching to the same gold wire?
There are many factors at play. One of which is the density of thiols on the surface. When you have enough thiols on the surface, they will arrange themselves in a 2-D lattice that is commensurate with the gold lattice (or something close to that). Once they are packed tight enough, they have to point up (actually they tend to lean, but that gets far to complicated and depends on the thiol length and lattice constant).
Another factor is the length of the thiols. If the thiols are short, then they won't want to bend over. If they are very long, they might bend a little. Also the bonding configuration between the atom on the end of the thiol and the gold surface might not allow for the thiol to lean very far.
Also, is there any evidence that gold is the only substance that this molecule shows preference to?
This is a very active field in Chemistry/Physics/Material Science. There are numerous materials that you can form these self-assembled monolayers on (gold, silver, InP, GaAs, etc...) but gold is probably the most commonly studied surface.
We played with alkanethiols on GaAs for a few months (several years ago) in our lab, but I haven't really been keeping up on the literature.
For a lot more information, do a search for "self-assembled monolayers" on google (or your favorite search engine). This field of research is huge and very interesting.
Is "solder" that disconnects when certain voltage is applied all that useful??? I mean this would be cool if it actually stuck, but it seems like the article is treating it more like a slow switch than a building adhesive...
That is not what they mean. When they say that the wires are self soldering and that when they ramp the voltage the conductivity drops, they don't mean that the wires melt and then fuse together and remelt and break apart.
What happens is the two gold "wires" are joined together by a long molecule whose ends preferentially bond to the gold. You can think of it like this, the "solder" is a string that has glue on both ends. You first coat material one with the strings and assume that only one end of the string will stick, the other end of the string now floats up in the air. You then bring the other material close by and the free ends of the string now stick to it. You have essentially bonded (or soldered) the two materials together with the strings. This is what is happening with thiols on gold.
Now the thiols only like to conduct one way (like a diode). When they reverse the polarity, the thiols stop conducting. The wires are still soldered together, it's just that they no longer conduct current between them.
A wire that could self solder seems to me would have a very low heat tolerance.
I don't believe that is the point. When they say that the wires are self soldering, they don't mean that the wires melt and then fuse together.
What happens is the two gold "wires" are joined together by a long molecule whose ends preferentially bond to the gold. You can think of it like this, the "solder" is a string that has glue on both ends. You first coat material one with the strings and assume that only one end of the string will stick, the other end of the string now floats up in the air. You then bring the other material close by and the free ends of the string now stick to it. You have essentially bonded (or soldered) the two materials together with the strings. This is what is happening with thiols on gold.
Seems this process might be able to make a couple thousand synthetic molecules, but how useful will it be at creating bulk quantities?
I wonder if these methods could be scaled up and automated?
Not likely. This is kind of question I get about my STM images. People ask me if I can just write a program to go in and automatically digitize the location of single atom defects. The problem is that it takes many years of looking at STM images just to get a feel for what you are really seeing.
This type of work is very long and tedious. I would be suprised you could make more than a couple of these molecules in an hour.
Slashdot Mirror
Pretty creepy stuff.
You could be seeing the results of that.
Looking at the holes in the fiber that they show in the pictures (with a scale), each hole is about 5 microns in diameter. I would highly doubt that water would completely fill these holes.
The water pressure at whatever depth they were set at could probably determine how far in each hole the water may have been forced. They could simply cut the line well beyond that and splice in a new fiber. Of course, I assume that they would have to do this in an environment free of water.
Phone Rings:
Me: "Hello"
Family member: "My computer isn't working"
Me: "Groan"
Next thing you know my dinner is cold and I am ready to put my fist through the wall.
There are many factors at play. One of which is the density of thiols on the surface. When you have enough thiols on the surface, they will arrange themselves in a 2-D lattice that is commensurate with the gold lattice (or something close to that). Once they are packed tight enough, they have to point up (actually they tend to lean, but that gets far to complicated and depends on the thiol length and lattice constant).
Another factor is the length of the thiols. If the thiols are short, then they won't want to bend over. If they are very long, they might bend a little. Also the bonding configuration between the atom on the end of the thiol and the gold surface might not allow for the thiol to lean very far.
This is a very active field in Chemistry/Physics/Material Science. There are numerous materials that you can form these self-assembled monolayers on (gold, silver, InP, GaAs, etc...) but gold is probably the most commonly studied surface.
We played with alkanethiols on GaAs for a few months (several years ago) in our lab, but I haven't really been keeping up on the literature.
For a lot more information, do a search for "self-assembled monolayers" on google (or your favorite search engine). This field of research is huge and very interesting.
Jeremy
That is not what they mean. When they say that the wires are self soldering and that when they ramp the voltage the conductivity drops, they don't mean that the wires melt and then fuse together and remelt and break apart.
What happens is the two gold "wires" are joined together by a long molecule whose ends preferentially bond to the gold. You can think of it like this, the "solder" is a string that has glue on both ends. You first coat material one with the strings and assume that only one end of the string will stick, the other end of the string now floats up in the air. You then bring the other material close by and the free ends of the string now stick to it. You have essentially bonded (or soldered) the two materials together with the strings. This is what is happening with thiols on gold.
Now the thiols only like to conduct one way (like a diode). When they reverse the polarity, the thiols stop conducting. The wires are still soldered together, it's just that they no longer conduct current between them.
Jeremy
I don't believe that is the point. When they say that the wires are self soldering, they don't mean that the wires melt and then fuse together.
What happens is the two gold "wires" are joined together by a long molecule whose ends preferentially bond to the gold. You can think of it like this, the "solder" is a string that has glue on both ends. You first coat material one with the strings and assume that only one end of the string will stick, the other end of the string now floats up in the air. You then bring the other material close by and the free ends of the string now stick to it. You have essentially bonded (or soldered) the two materials together with the strings. This is what is happening with thiols on gold.
Jeremy
Not likely. This is kind of question I get about my STM images. People ask me if I can just write a program to go in and automatically digitize the location of single atom defects. The problem is that it takes many years of looking at STM images just to get a feel for what you are really seeing.
This type of work is very long and tedious. I would be suprised you could make more than a couple of these molecules in an hour.
Jeremy
http://stmlab.tamu.edu/