Hello from Oklahoma.

[RamanShift]

I am an undergrad, interested CG via ultrasonics.

[Kephra]

Have you worked out a process yet?  I know that ultrasonics can be used to disperse nanoparticle powders into solution, but can gold nanoparticles actually be produced that way?

[RamanShift]

Dispersion of nanoparticles is precisely why we got the bath (CNT's to be exact). It seems to be the least destructive method for CNT dispersion.

I haven't had the time I would like to do much work with spontaneous gold particle formation via ultrasonics. I read a paper, and I continuously kick myself for losing it, that detailed a method for formation in pentanol I believe.

I use the US bath to aid inter-micellular interaction. This allows me to produce two separate solutions of a surfactant at CMC (or Heptane and Propanol w/CTAB) one of which has an aqueous solution of HAuCl4, and the other containing the reducing agent/s. I've used citrates, and maltodextrin. My hope, and I've yet to get any samples under the AFM to verrify this, is that the ultrasonication will insure a more uniform micelle-micelle mixing, resulting in a more monodisperse colloid. This process can be done without the US bath though. Simply shaking the container containing both parts is enough to produce.

I've yet to work out the bugs in this method. My ultimate goal, is to find method that would allow a continuous production process, preferably in a variety of solvents. This is the reason i'm looking into ultrasonics.

[Kephra]

I read a paper, and I continuously kick myself for losing it, that detailed a method for formation in pentanol I believe.

This looks interesting.

[RamanShift]

I preformed a series of quick experiments similar to those in the paper today, with different results. I don't have 1-propanol, only 2, but I do have pentanol. I only had time to test the effects of SDS concentration . And I only used 2-propanol. I could only get a blue colored colloid. From no SDS all the way to CMC at 8mM, I didn't notice a change in color. The samples have some interesting optical properties I've yet to see with gold. Transmitted light is the blue color, but reflected light is a dark, almost rusty brown color. What's more, the angle off of center of the light source at which the color changes to red is only around 15*. I'm assuming they flourece like crazy so I think raman spec is out of the question. I prepped a couple of samples for the AFM. I'll check them out tomorrow. And if the various colloids haven't aggregated overnight, I'll check them out on the spectrometer. Perhaps the surfactant did change something minutely.

[Liam]

Hello RamanShift,

Is your research aimed at a particular use, like biology, or is it pure materials science.  The reason I ask is that almost everyone here is here because we make CS and CG to ingest for one reason or another.  If anything you publish here results in toxic materials (more toxic than pure silver or gold) please make that known.

BTW, it must be great to have such great lab equipment to use   Some of us have nothing more than mason jars.

[RamanShift]

Is your research aimed at a particular use, like biology, or is it pure materials science.

I'm mainly interested in the production process, though not for any particular (pardon the pun) application. Biology isn't my forte, which brings me to the toxicity bit. I would not consume any of the above chemicals, water being the exception of course, in any amount that would be substantial enough to produce CG. 2-propanol is "rubbing alcohol" and pentanol is definitely not good to drink.

Though I will make note of toxic substances in the future, it seems to me that anyone who can get their hands on most of the chemicals I use, will most likely have that ability due to their being a student, chemist etc. In the event that the un/ill-informed does acquire harmful chemicals, and decides to consume them without doing their due diligence, would probably not head my warning. Though as I stated previously, I don't mind doing so, and agree that it's a good idea.

The equipment is extremely nice to have. I spend as much time as I can using it. Lab-glass is just fancy/expensive Mason jar anyway.

[Kephra]

Is your research aimed at a particular use, like biology, or is it pure materials science.

I'm mainly interested in the production process, though not for any particular (pardon the pun) application.

Nothing wrong with that.... you figure out how to make it or how to make it better, and someone else will figure out what to do with it.

Biology isn't my forte, which brings me to the toxicity bit. I would not consume any of the above chemicals, water being the exception of course, in any amount that would be substantial enough to produce CG. 2-propanol is "rubbing alcohol" and pentanol is definitely not good to drink.

Though I will make note of toxic substances in the future, it seems to me that anyone who can get their hands on most of the chemicals I use, will most likely have that ability due to their being a student, chemist etc. In the event that the un/ill-informed does acquire harmful chemicals, and decides to consume them without doing their due diligence, would probably not head my warning. Though as I stated previously, I don't mind doing so, and agree that it's a good idea.

Yeah, that is a good idea.  There are always people in the world who have extremely poor judgement and we do not know who is going to read our words.  A forum is like a conversation in a crowded room, its hardly private.  And as it is, I get hate mail from my youtube videos. Who would have thought? 

The equipment is extremely nice to have. I spend as much time as I can using it. Lab-glass is just fancy/expensive Mason jar anyway.

I'm jealous   Although I really don't like doing lab work.... I break too much stuff, which is why I opted to major in physics instead of chemistry a very long time ago.