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At the Techconnect Nanotech 2011 conference in Boston a couple of weeks ago, the emphasis was clearly on the ‘downstream’, i.e. realising the potential of nanotechnology in new and exciting products. I was impressed by the progress made at Nanocomp in manufacturing huge sheets and yarns from nanotubes for applications such as EMI shielding and heat straps. Having shared the lab with folks wondering how one could process this stuff in the nineties  the presentation brought it home how far the field has developed in the last 15 years.
Going from the large size applications to the small, Tom Russell presented the latest in his quest to reach addressable arrays of 10 tera-dots per square inch by self-assembly of block copolymers. A fascinating journey, from the enhanced ordering obtained by solvent annealing which gives grain sizes of about 20 micron (“not good enough”), lithography guided assembly (“still not good enough”), to spin coated and solvent annealed copolymer on faceted sapphire wafers, which eventually lead to cylinder phase perpendicular to the sapphire ridges with translational and orientational order persisting over centimetres! Looks like the next generations of memory devices is well on its way.
Big strides are also being made in catalysis. Nanostellar, who design new materials based on a so-called Rational Design Methodology which relies heavily on simulation, presented advances in diesel emission catalysts. It was interesting to hear from CEO Pankaj Dhingra that their focus has changed from using modelling for wide range screening to a more focussed application on uncovering the key selection criteria within a more targeted phase space, in this case Strontium doped Lanthanum perovskites.
The downstream theme was also echoed in the modelling session. Apart from my talk about the ‘landscape’ of integration of atomistic simulation into engineering optimisation, which I’ll come to in another blog, Simon McGrother from CULGI highlighted some great successes of polymer and mesoscale modelling in product development. Despite that, he made the point that these methods have still not reached the ‘democratization’ that was anticipated ten years ago. Based on the growth figures of the modelling community presented in my previous blog, I would actually dispute that. Nevertheless, the impact on ‘downstream’ development and products remains limited, and that’s where I agree with Simon.
On the other hand, the engineering simulation community is showing an interest in molecular modelling, as highlighted in a presentation by Carlos Alguin, Head of the Nanotechnology Group at Autodesk with some cool graphics based on the Maya software and Molecular Maya toolkit. Clearly, the ease of use of and interactivity their design tools and the superb visualization have much to offer the molecular modelling community. The question is though how we achieve further awareness and utilisation of materials modelling back in the engineering world.
 M.S.P Shaffer, X.F. Fan and A.H. Windle, Dispersion and packing of carbon nanotubes, Carbon, Vol. 36, No. 11, pp.1603-1612 (1998)
The atomistic modelling field has grown substantially over the last 10 years, and reached a level of maturity which makes a more routine type of application and integration into engineering and product design a viable option. At the same time, product design has reached scales that are close to atomistic, and also involves exploring an ever larger space of potential new materials across the element table.
Here is some evidence:
The growth of the simulation field was demonstrated very nicely by a recent study based on publications in the ab initio field by the Psi-k network. It shows a strong increase in the number of (unique) people publishing papers based on ab initio methods from about 3000 in 1991 to about 20,000 in 2009, with particularly strong growth in East Asia. If one adds people who use other techniques such as molecular dynamics, and researchers in industry that don’t publish their work, it should be safe to assume that there are more than 30,000 users of some sort of atomistic technique.
This level of growth is also linked to the robustness of the codes and the speed of standard hardware. These together with the experience that has been gained regarding the types properties that can be calculated at a certain level of accuracy have increased the impact of atomistic simulation in many industrial applications.
Also, atomistic techniques support the combinatorial exploration of the large materials phase space. For example, the iCatDesign project in the UK explored alloys for fuel cell catalysts, considering both the combination of different elements as well as structural aspects. The online library of binary alloys from the Energy Materials Lab at Duke is an example of structure calculations that aid in the discovery and development of new materials. Considering ternary alloys are becoming more important in meeting complex requirements in high performance applications such as aerospace and energy generation, and the fact that only about 5% of ternaries are known, such modelling approaches will become even more relevant in new materials design. Also, in other areas such as polymer and composite design, early adopters are demonstrating the usefulness of integration, for example Boeing reported that they “integrated molecular simulations into the materials design process” and their work “demonstrates that the future of aerospace materials development includes simulation tools”.
Despite the growing importance and opportunity of a stronger integration of atomistic methods into engineering design, this is still an area in its infancy, but promoted strongly as part of a wider agenda such as Integrated Computational Materials Engineering (ICME). One of the key questions I am interested in is how the integration is actually achieved. For example, will integration of the modelling methods themselves be required, as in multiscale methods?
While multiscale methods are important for some applications, their significance for integration may be overrated, as was also concluded by the report on ICME report. Rather, the focus needs to be on a more detailed analysis of design workflows, and their intersection with the information that can be determined well at the atomistic scale.
A design workflow typically includes a number of selection stages, at which decisions are made regarding materials and processes. These will be informed by available data from a number of sources and should include atomistic modelling where appropriate. This type of approach has been reported for example by Massimo Noro from Unilever, who talks about selection criteria as “emerging physico-chemical criteria we can evaluate in practice that help us select ingredients”. Also Oreste Todini from Procter & Gamble promotes the use of modelling in the decision process to come up with lead options for new formulations.
So there is evidence of an integrated design approach from early adopters such as Boeing, Unilever and Procter & Gamble. In order to establish integration more widely, engineering and science communities need to collaborate more closely. The atomistic simulations community needs to improve the way in which best practices are established, shared and linked with engineering workflows. Informatics frameworks are being established, for example with the integration of Materials Studio in Accelrys’ Pipeline Pilot platform, and projects such as iCatDesign and MosGrid. However, integration into engineering rather than chemistry platforms may be what is required.