Playing the Polymer Game

Over the last two decades, increasing attention has been paid to the analysis of complex polymers, particularly determining their chemical composition and microstructure using advanced fractionation and spectroscopic methods. Why do we need this information? So we can fully understand the behavior and properties of materials during processing and application. The precise analysis of such materials – which have multivariate distributions – is a difficult task, and a single separation/analytical method is often not able to provide comprehensive information.  

The most commonly used techniques include size exclusion chromatography (SEC) and MALDI-MS. However, it is important to be aware of the limitations of these techniques, and to keep an open mind to other separation techniques that can supplement them. For polymers with more specific applications, such as polymers with functional groups (for good adhesion and so on), block copolymers (for morphology control) and polymers with well-defined molar mass distribution with architecture, neither SEC or MALDI alone can provide sufficient information.

In short, the characterization of polymer molecular heterogeneity demands the use of a wide range of analytical fractionation techniques, preferably those that are selective towards a specific type of heterogeneity. We call this “analytical LEGO” and, just like in LEGO – where kids put toy bricks together to build complex structures - we combine analytical components to build complex analytical instrumentation. For example, multidimensional and multidetector column- and channel-based fractionations provide exciting avenues in method and technology development (1, 2, 3). (And complex polyolefins represent a good example of when such complex methods are necessary, as only a combination of different analytical methods can address all the molecular parameters (4, 5, 6)).  

Another interesting multidetector fractionation technology is field-flow fractionation (FFF), of which thermal FFF is a subtechnique. Thermal FFF can fractionate micelles, vesicles, nanogels and other polymer assemblies according to size, composition and molecular topology (7).  

Research on these approaches – and more – will be presented at the International Symposium on Separation and Characterization of Natural and Synthetic Macromolecules (SCM). This biannual conference brings together scientists who share an interest in the separation and characterization of “large” molecules, and is one of the most important forums for discussing the basic principles of multidimensional fractionations (and their capabilities in chemical composition and microstructure analysis). For us and our students, SCM is essential – it’s an opportunity for chromatographers and spectroscopists alike to present ideas and take part in lively discussions.  

This year, we are presenting a workshop called “Polymer Separation – Learn from the Best.” Targeted at analytical and polymer scientists, chemical engineers and laboratory managers, as well as postgraduate students and lab technicians, it will provide a state-of-the-art overview of polymer fractionation and characterization, addressing both fundamentals and the latest developments in the field. Our message is: if we want more detailed characterization of molecules in polymer analysis, it’s time to get out the analytical LEGO. “Playing” is rewarding… and fun!