Colloid & Surface Chemistry


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Councilors' Statement on Divisional Name Change

Posted on November 9, 2012 at 2:50 PM

Division Name Change: Councilors Reflect on the Past, Present and Future of the

ACS Division of Colloid and Surface Chemistry 

The Division of Colloid and Surface Chemistry is in the process of formally proposing to the American Chemical Society to change its name to the Division of Colloids, Surfaces and Nanomaterials. Division members voted electronically on the question of whether to change the name, and over 90% of respondents voted in favor of the proposed change. More recently, some ACS members affiliated with other divisions have asked why our division is adding nanomaterials to its name, especially when nanomaterials are relevant to the activities of several other ACS divisions. Is this an attempt to stake a territorial claim to all ACS programming in the area of nanomaterials, to the detriment of other divisions? 

The answer to these questions is that the division seeks to incorporate into its name the terminology that is rapidly becoming the standard scientific terminology to describe the colloidal system - the material system that has always been the focal point for our division's scientificmission since it was established in 1925. This is not staking claim to new scientific "turf". It is simply a recognition that increasing numbers of scientists use terms such as"nanomaterial"or"nanoparticle" to describe precisely the class of systems that has always been known as a colloidal system.

Wolfgang Ostwaldwas the first chemist to specify a size range for colloids. In his book An Introduction to Theoretical and Applied Colloid Chemistry: The World of Neglected Dimensions(Authorized translation from the eighth German edition by Martin H. Fischer, John Wiley & Sons, New York, 1922), Ostwald stated that "Colloids are dispersed systems, in which the diameter of the dispersed particles in typical cases lies between one ten-thousandth and one one-millionth of a millimeter." Texts more modern than Ostwald's but still written before the nanotechnology revolution, such as Principles of Colloid and Surface Chemistry, by Paul Hiemenz and Raj Rajagopalan (Marcel Dekker 1997), define a colloid as "any particle that has some linear dimension between 10-9 m and 10-6 m". A new textbook, written well into the nanotechnology revolution, An Introduction to Interfaces and Colloids, the Bridge to Nanoscience by John Berg (World Scientific 2010), defines the linear dimension of colloids to be in the 1 nanometer to 10 micrometer range. This size range is repeated across the spectrum of modern colloid science textbooks. 

While the upper bound on the defined size of a colloid has increased since Ostwald's earliest specification, the lower bound of 1 nanometer as the definition of a colloidal system has never been challenged. The paradigm behind colloid chemistry has long been that colloids are a unique state of matter where system properties are dominated by surface phenomena, hence the ACS journal Langmuir, carries the subtitle The ACS Journal of Surfaces and Colloids.Nanomaterials are at the core of the science that this division has always embraced.The paradigm of surface-dominated behaviors, whether they concern nanoparticles, nanostructured materials or micrometer scale objects, has always driven the field forward. We recognize and accept that other divisions include nanomaterials as a subset of their scientific mission, but for this division they are central to our mission. 

To illustrate the trend in scientific terminology that is driving the proposed name change, consider how scientists refer to colloidal gold, the nanoscale material that lends a brilliant ruby red to medieval stained glass. Faraday's famous suspension of colloidal gold (now known as "gold nanoparticles" or "nanogold"), which has resisted aggregation for well over a century, is a standard textbook example for howthe surface chemistry of colloids can be manipulated to slow down the particle aggregation process that is thermodynamically inevitable. A Google Scholar keyword search on the term "colloidal gold" in patents and scientific articles, limited to the years 1900 - 1999, the year before the launch of the United States federal government's National Nanotechnology Initiative yields 46,200 hits. A keyword search on "gold nanoparticle" in the same time window yields just 2,240 hits. Change the time window to 2000 to 2012, the era of the nanotechnology revolution, and the results are striking. The term "colloidal gold" yields 66,900 hits and "gold nanoparticle" yields 79,900!While research on colloidal gold and its applications has clearly accelerated, venerable "colloidal gold" has been overtaken by the new terminology in just 12 years. Yet these terms describe the exact same state of matter.

Is this just an effort to "modernize" or to be "trendy"? Why does it matter which terminology is used if good science is being conducted? The division believes this name change is scientifically necessary because ensuring that proper information exchange occurs among diverse researchers is essential to our mission. Researchers who look at our division should know that we investigate nanomaterials. Younger investigators need to know that there is a vast wealth of scientific understanding at their disposal in the colloids literature, which is the foundation forthe "nanomaterials" literature. The mission of ACS divisions is to advance the chemical sciences. In the case of nanomaterials chemistry, this mission is served by taking measures to ensure that practitioners who work on the same systems but use different vocabularies do indeed come together to advance the science.

Other divisions have expressed concern about programming and membership, since several other divisions certainly do program actively in nanomaterials. Just as the Division of Colloid and Surface Chemistry supported the creation of the new Division of Catalysis Science and Technology, despite a long history of programming in the surface science of heterogeneous catalysis, the division in no way intends to interfere with the ability of other divisions to program in the nanomaterials area.Furthermore, our division has a long history of programming jointly with other divisions, andis eager to program jointly with other divisions who investigate nanomaterials. Since its inception, the division has emphasized the fundamental principles underlying the behavior of all colloids, including the 1 - 100 nm colloids now called nanoparticles. The division also encompasses surface science as a major focus (currently we are the Division of Colloids and Surface Chemistry) Why? Colloids and nanomaterials are dominated by their surface properties. Consequently, much of the surface chemistry programming of the division focuses on nanostructured materials and nanostructures supported on surfaces, both falling under the umbrella of "nanomaterials". The scientific concepts the division has promoted have led to many applications of these materials. Divisions representing technical areas where nanomaterials can be exploited to advantage, whether in novel food structures, new heterogeneous catalysts, new drug delivery vectors,or new materials derived from renewable forest products, should certainly feel encouraged to develop relevant programming. When the interests of divisions overlap, for example when symposium organizers seek to cross-fertilize ideas from different application areas or fundamental concepts, this division will eagerly welcome joint programming to the benefit of the science.

It is important for all of us that the American Chemical Society be a society that embraces change and modernization so as to best reflect the times we live in. The division name change encourages such modernization.