Unfortunately yes, Colloid Science in general and Colloid Chemistry in particular have been metabolized by Nanotechnology during the Nano-hype. The hype became a tool to access funding using flashy concepts. The concepts of the Colloidal Science are still here, they are the foundation, not the bubble as Nano. Foundations always stay, while bubbles pop up or deflate.

@ John Francis Miller

I share your point of view. For this, so that discussion is not a useless conversation, I attach a file on the terminology of colloid chemistry.

Colloids are disperse systems, in

which one phase has dimensions in the order of 1 nm to 1 μm. The word

“colloid” comes from the Greek word for glue and has been used the first time in 1861 by Graham. He applied it to materials which seemed to dissolve but were not able to penetrate a membrane, such as albumin, starch, and dextrin. A dispersion is a two-phase system which is uniform on the macroscopic but not on the microscopic scale. It consists of grains or droplets of one phase in a matrix of the other phase.

Personally, I think the question is not how to describe "nano" or "colloid", the point is that there is an interface between phases of the investigated system. If there is an interface and the interface has influence on the behavior of the system, then we are talking about colloid chemistry or surface chemistry.

Unfortunately yes, Colloid Science in general and Colloid Chemistry in particular have been metabolized by Nanotechnology during the Nano-hype. The hype became a tool to access funding using flashy concepts. The concepts of the Colloidal Science are still here, they are the foundation, not the bubble as Nano. Foundations always stay, while bubbles pop up or deflate.

It all changed rapidly and went downhill when the 'so-called nano' revolution started off with hype in around 2004 in the US. I heard the leader of this 'revolution' spout that nano in catalysis only began when the this NSF funding started and that there was zero nanotechnology before then in that field. Piffle.

For example, supported metal catalysts (my Ph.D area) have been known for decades and these all contain metal or alloy particles < 100 nm sterically bound to the support. Look at 5% Pd/C catalysts for hydrogenation, for example. I considered my work in the 1970's on gold, Pt, and Pd materials as colloidal chemistry and we measured in Angstroms not nanometers...

'Green' production of nanoparticles is another area that's been abused - there seems to be no awareness that the 'green' part of this contains the reducing agent and that the source of the nanoparticles is some precursor such as AgNO3 or HAuCl4.xH2O

So, I agree, John, the terms have been abused and one of the drivers is the funding opportunities by including such terms as 'Leading Edge Green Bio Nano Terrorism instrumentation'.

I think that between the colloid science and the nanoscience exsist the difference. For example, in the nanostructure. Between neighbouring nanograins in the alloys which have the size from 50 nm to 100 nm create to intergrain exchange interaction. Thus, that of the intergrain exchange interaction don't have in the colloid.

@

I recently posted a brief article about nomenclature (taken from a short course):

http://enlightenscientific.com/2018/12/07/you-say-nano-i-say/

The key message I put across is that it doesn't matter what you call it, the most important thing is the answer to this question:

Can the fundamental concepts of colloid science be applied to my products to improve their quality and reduce waste?

So you can say about each direction of science and technology. It is necessary to interact with nature so as not to harm it.

John, yet, committees spend hours developing definitions and nomenclature. In the past, two hours were spent on the argument between cocrystal or co-crystal and the group did not reach the consensus at that time.

It is the problem of committiees, Andrei.

Thanks for the great question John. Needless to say, I fully agree with your point of view. Plenty of good answers already, but I feel the need to add my 2 cents. I passed the "famous" MSc course in colloid science at Bristol University in 1976. We had two FRS amongst our lecturers: Ron Ottewill and Douglas Everett. It set me up for a life in research.

"Colloid science" sounds so old hat now, but it is not the same as nanotechnology. Of course, "nano" + "anything" is partly a fashionable way to get grants.

Acknowledging that you are "just" applying theories solidly founded (many) decades ago is not as sexy as exploring "novel" concepts. Also it might involve actually photocopying old papers or even ... going to a library to read an old book - unthinkable for the young, I imagine.

So, what if anything, can be done to bring back colloid science into focus as a coherent body of thought?

Thank you for bringing this up, Dr. John Francis Miller .

Coming from the sub-field of "solar nanofluids", and being a PhD candidate in Mechanical Engineering, I had almost no background in colloidal science.

Fortunately, when the time came to deal with colloidal stability of nanoparticles, I had to build a good background on colloidal science before delving into any stability analysis of nanofluids.

I did that by taking some time off to carefully read relevant chapters from the classical books of Israelachvili, Hiemenz, and Elimelech, among many others. I ended up with countless pages of personal notes. It is definitely not the same as receiving academic training by courses, but it was a fascinating experience, to say the least!

And based on my high exposure to the nanofluid literature, I can't agree more that so many pitfalls could be avoided when nanotechnology, in general, is analyzed with the aid of established theory in colloidal sciences.

I also really benefited (and most likely, will always do) from following the discussions, answers, and explanations of Yuri Mirgorod , Alan F Rawle , and John Francis Miller on RG. Something I am really grateful for!

Here's an example of new and unnecessary terminology:

"The key role of protein-nanoparticle interactions in nanomedicine and nanotoxicity has begun to emerge recently with the development of the idea of the nanoparticle-protein ‘corona’. This dynamic layer of proteins (and other biomolecules) adsorbs to nanoparticle surfaces immediately upon contact with living systems."

Article Protein-nanoparticle interactions

This paper has more than 1100 citations and the term 'corona' has been firmly established.

'Corona' is just Latin for 'crown' but is used to imply a dynamic structure, presumably because of the plasma around the sun. But the sun's corona is called such because, when visible during an eclipse, it resembles a crown. It has nothing to do with dynamics. A layer of proteins at or near a particle surface bears no resemblance to a crown.

Now there's a body of papers in a discipline using a non-obvious term for what is just the adsorbed protein layer. Physisorption implies equilibrium. The new term is unnecessary and, outside of the discipline, confusing.

John, thanks for the pointer: reasons to be grumpy part 98... The Dutch colloid scientists had a whole string of beautiful papers on this back in the 70's and 80's. I'll happily bet that they won't get a mention in this reincarnation.

https://www.researchgate.net/publication/258852229_The_Limitations_of_an_Exclusively_Colloidal_View_of_Protein_Solution_Hydrodynamics_and_Rheology

Why so divisive? Identifying the shortcomings of one theoretical framework and putting forward an improved theory is laudible. But, just because some researchers in one small segment of a large discipline attempt to invoke a model that doesn't always work (lyophobic hard spheres), it isn't justifiable to trash the entire discipline which is the undercurrent in this article.

Language such as:

"They are charged like colloids, but unlike colloids" - they ARE colloids. This shows a disturbing lack of understanding.

"Here we overturn entrenched doctrine..."

"dual macromolecular and colloidal characteristics" - macromolecules in solution are colloids. There's a journal called Macromolecules (published since 1968) dedicated to polymer and interface science.

Perhaps reading a paper such as this one below would illustrate the cutting edge of the science:

Article Deconvolution of the Effects of Binary Associations and Coll...

The first article comes across as thinking colloid science hasn't progressed since the 1980s and that the concepts used is this paper are novel and outside the realm of colloid science. Nothing could be further from the truth.

EDIT: I found this paper:

Article Theory of Protein Titration Curves. I. General Equations for...

that shows that this issue was being addressed as early as 1957.

As a new generation scientist working with noble metal colloids, I totally agree. The best example I think is lack of understanding for the differences between "aggregation" and "agglomeration". In newer literature this is seldom discussed and often looked at as the same thing.

Hi John and everyone.

I just read about this important point that John raised and would like to share with you a quotation that could frame the actual status of colloidal science. From my perspective, I think that the "rediscovery" of very well known phenomena is not only due to a lack of literature revision but also to the wide number of new systems under scrutiny which "test" the applicability of concepts and approaches, so important for mature science. The following are the premonitory words of William Clayton in an article titled “The need for research in colloid chemistry” ( Nature volume 108, pages586–587 (1921) ) and clearly express what we now, almost a hundred years after, can testify:

" Colloid chemistry has never been discussed so frequently as it is today. (...) Certain it is that no branch of applied chemistry to-day can be declared free from colloid problems and that the chemistry of to-morrow will be colloid chemistry, pure and applied”.

(PDF) Special Issue: Iberoamerican research in bioapplications in colloids and surface science. Available from: https://www.researchgate.net/publication/272785873_Special_Issue_Iberoamerican_research_in_bioapplications_in_colloids_and_surface_science [accessed Oct 15 2019].

Thank you Jhoan Toro-Mendoza - that's a very interesting (if saddening) quote. Since my original post, I have done some research that has led me to the point of writing it up for publication. It relates to titration and electrophoresis of protein solutions. My results were puzzling. I found vast bodies of research from the 1920 - 1940s that helped explain a lot of my observations. It is quite humbling to see the quality of the work that was achieved without modern technology. I could have easily not bothered reviewing the literature and, instead, written a paper claiming to have found some new phenomenon.

The further I dug into the nanomedicine literature, the more shocked I became at the fundamental errors as far as understanding colloid science is concerned.

I don't have an institutional subscription for journals but have managed to get 150+ relevant papers of which I've paid for about 10.

I have an unusual vantage point. I got my PhD in 1990 and then worked in industry for ~25 years. I didn't stay close to the colloid literature. Now I am back in the colloid world and can see a significant shift and an almost universal lack of awareness of any research done before 2000. I was fortunate to do my PhD in a leading colloid group that interacted with a couple of other equally renowned groups. Together, they developed powerful theories for predicting the complicated behavior of polymers at interfaces which is directly relevant to the "protein corona" focus in nanomedicine. But I have not found one reference to it. This includes large bodies of work led by someone who is editor-in-chief for a leading colloid journal. I cannot believe he doesn't know of the previous decades of research yet it's never mentioned.

John Francis Miller " : It is quite humbling to see the quality of the work that was achieved without modern technology. "

It is so true. People had more time to think back then, now we are too busy pushing the buttons.

John Francis Miller , thank you for sharing your last year's pathway and your first-hand experience on the development of theories predicting the protein corona. Doubtlessly and sadly, it is one example of several others of oversight scientific contributions: It seems to be a part of the current research funding structure and also, as Andrei Burnin says, we are too busy pressing buttons, in a rush for appealing results.

However, I also think that there are many others that, like us, are not only aware of the situation but contributing to putting an order in the mess. I invite you to take a look at this wonderful article from Thomas Mason which, in a very authoritative and educative manner, contextualize part of the discussion we are having

Article Emulsiogenesis and the Emergence of Nanoemulsions

I am willing to read your manuscript with the results of your search and analysis.

Indeed. There is a "black box" mentality with many modern techniques that have reached maturity and are accessible with commercial instruments. Unfortunately, it hides a lot of the assumptions that you have to know. For me, the classic example is zeta potential measurement which, in fact, is an estimate based on measurement of electrophoretic mobility. The right electrokinetic theory has to be used according to your particular sample. But modern instruments hide this and, without an proper understanding of colloid science, most users are unaware. Such instruments are used like UV spectrophotometers - put your sample in and get a number. After that, the likely erroneous information is misinterpreted by using the wrong theory. Probably 90% or more papers that include zeta potential measurement either don't specify how it was measured or, if they do, the conditions (pH, salt concentration etc).

As a result, they come to the conclusion that colloid science doesn't work. The most stark example of this is:

Sarangapani, P. S.; Hudson, S. D.; Migler, K. B.; Pathak, J. A. The Limitations of an Exclusively Colloidal View of Protein Solution Hydrodynamics and Rheology. Biophysical Journal 2013, 105 (10), 2418–2426. https://doi.org/10.1016/j.bpj.2013.10.012. Here are the first three sentences of the abstract:

"Proteins are complex macromolecules with dynamic conformations. They are charged like colloids, but unlike colloids, charge is heterogeneously distributed on their surfaces. Here we overturn entrenched doctrine that uncritically treats bovine serum albumin (BSA) as a colloidal hard sphere by elucidating the complex pH and surface hydration-dependence of solution viscosity."

Let's see...

1. Proteins *are* colloids. Well, if they are in solution.

2. The "doctrine" is DLVO theory which, as Verwey explains very clearly, is limited to lyophobic rigid plates or spheres with uniformly distributed charge. It's the people incorrectly applying the theory to their lyophilic soft/porous particles that are at fault, not the science.

3. The connection to viscosity was studied at length in the first half of the last century

What can we do?

Perhaps we should petition colloid journals that allow these papers to be published to pay more attention to the misinformation that is now becoming the de facto science that new researchers turn to.

It's so saddening to me.

Jhoan Toro-Mendoza That's a great article. Thanks for the reference. He speaks about this situation the way I do.

I thought I was losing it when I got back into the field and saw "nanoemulsion" and wrongly-described "microemulsion". My fellow PhD students worked on microemulsions so I thought I understood them (which I do)! So, now we have confusing nomenclature and concepts that simply aren't grounded in physical chemistry.

As I read review articles on protein corona, I noticed two things:

1. The word colloid (or derivatives) appeared either once or not all (except in references to journals with the word in the title)

2. No references to papers prior to 2000 or so

3. Sweeping statements with no reference to primary material (e.g., DLVO theory)

If I did 2 or 3, my supervisor and the journal reviewers would come down on me very hard. Journal editors shouldn't be allowing this.

It bothers me that I have to learn a new vocabulary for my formal discipline because of the money grab for nano grants.