Final Report Summary - MICSED (MICSED - Molecular Interactions in Complex Systems) The MICSED European Industrial Doctorate (EID) programme (https://micsed.wordpress.com/) was a partnership between the University of Durham in the UK and Procter and Gamble (P&G) Research Centres across Europe (Schwalbach Germany, Brussels Belgium, Pomezia Italy and Newcastle UK) which are tasked with driving product innovations in the consumer goods sector. Durham University is one of the UK’s leading research-intensive Universities and P&G is the world’s largest consumer packaged goods company, currently serving 4.6 billion of the world’s 7 billion consumers.Over the past 100 years consumer products have developed from often simple one or two component formulations into highly sophisticated and complex non-equilibrium multi-component systems. This complexity has been driven by a consumer desire for higher performance and higher convenience items. There are enormous and often conflicting demands placed on these products – they must remain perfectly stable during production, shipping and storage, yet show high performance and efficacy at the point of use. Designing this balance of stability and activity is an enormous challenge. At the same time companies and consumers have strong ethical and economic reasons to provide and use goods with minimum environmental impact. This includes the energy and packaging inputs needed during production, shipping, storage and use as well as the eventual end-of-life environmental impacts of product disposal. The consequent requirement of “just-sufficient” product engineering is a major challenge. It was (and remains) clear to both project partners that effective product innovation can only be achieved through a molecular-level understanding of the physical and chemical processes at play in products. The Molecular Interactions in Complex Systems European Industrial Doctorate (MICSED) network was designed to produce a cohort of individuals trained to meet this important challenge.The research aim of MICSED was to develop and apply toolkits of experimental and theoretical methods which could be applied in four main areas (and reapplied in others): (1) An understanding and control over small molecule migration through polymer matrices of importance in applications such as adhesives in baby care products and active molecules in laundry formulations; (2) Control over the formulation and deposition of hueing dyes and brighteners in detergents; (3) Controlling the stability and efficacy of enzymes used to enable energy-efficient lower washing temperatures in laundry applications; and (4) Providing detailed mechanistic understanding of the key radical species underpinning a range of cleaning products.Five talented and hardworking Early Stage Researchers were recruited to tackle these important challenges. They joined the programme after completing undergraduate degrees in Physics, Polymer and Physical Chemistry, Engineering Chemistry, Pharmaceutical and Biomedical Chemistry and Environmental Chemistry and worked with 11 academics from Durham and 8 research scientists from P&G. This interdisciplinary team was key to the project’s success. Significant progress was made in each area, which we summarise briefly below. Each of the ESRs has written up their research findings as PhD theses, and we anticipate they will be awarded doctoral degrees over the next twelve month period. Through training these individuals (with the help of our training project partner Epigeum) we have met one of MICSED’s principal aims of providing talented interdisciplinary researchers capable of working at the university-industry interface and meeting the innovation challenges required by European industries.ESR1 and ESR2 worked on the challenging problem of modelling small molecule migration through polymer mixtures of which one component is a gel – this is an important problem in a range of consumer goods applications. ESR1 focussed on the theoretical aspects of the problem and developed a novel free energy functional that incorporates gel elasticity and excludes network entropy which was used to compute (a) migrant fractions for miscible, and (b) thickness of wetting layers for immiscible mixtures. The work, published in PRL, showed that surface segregation can be significantly reduced and the wetting transition avoided by increasing the bulk modulus of the gel. The results were compared against experimental data produced by ESR 2, which led to a refinement of the proposed free energy functional. It is now possible to directly compare the theoretical predictions against experimental data for real polymer mixtures and predict the likely behaviour of real industrial formulations.ESR2 provided important experimental results concerning surface migration, which challenged existing theories and helped steer the work of ESR1. Her neutron reflectometry work showed that traditional models such as Schmidt-Binder required modification to capture the concentration profile of polymer/oligomer films around wetting transitions. Understanding this near-surface composition is essential to optimise the use of hot-melt adhesives. A comprehensive study on the interplay between surface energy, compatibility and surface composition, linked to computational simulation was published in Soft Matter. ESR 2 further demonstrated that aliphatic tackifiers, previously assumed to be excluded from glassy blocks in hot melt adhesives, can become incorporated during the thermal cycling of hot-melt adhesives. Further publications combining the theoretical work of ESR1 and experimental work of ESR2 are in preparationESR3’s project involved investigating surfactant-dye interactions to limit unwanted dye staining (both accidental dye migration and over-deposition of optical brightners) during laundry processes. UV-vis spectrometry, small-angle X-ray scattering and NMR techniques were used to determine surfactant-dye binding constants and identify the location of the dye in commercially important surfactant micelles. The influence of forumulation viscosity formulations, surfactant-dye binding constants and chemical tailoring of surfactant to dyes were investigated.ESR4 investigated the key reactive oxygen species, ROS, that are used to oxidise highly coloured stains during laundry processes. These are typically highly reactive and short-lived species generated in situ from stable precursors The project led to a detailed understanding of the identities of the ROS generated by different precursors and how their concentrations in the wash liquor change during the wash cycle. One of the early challenges of the work was creating a set of analytical methods for selective identification of different ROS without interference from other species. Once these were in place ESR4 was able to monitor the rate at which various bleaching agents are generated as the formulated laundry product is added to water, followed by their removal due to reaction with model ‘stain’ components. The work progressed from idealized systems in dilute solution to the study of ROS created under real washing machine conditions. The experimental toolkit is readily reapplicable to a range of different chemical systems in both academic and industrial contexts.Finally, ESR5 investigated mechanisms of protein denaturation in complex fluids focusing on the key enzymes utilised in current laundry formulations (amylases, proteases, lipases). A major challenge was to overcome the interference of the high concentrations of surfactant with techniques used to probe denaturation, and method development to reduce these complications. A combination of differential scanning calorimetry (DSC) and fluorimetry (DSF) together with circular dichroism (CD) successfully provided mechanistic insight in these surfactant-rich environments, and individual roles of surfactant, binder, chelant and buffer could be established. A key aim was to determine whether these alternative methods could provide additional insight into earlier-onset protein decomposition not revealed through conventional enzyme storage experiments. Distinct enzyme-dependent differences were revealed in correlations of Tm data obtained from DSC, DSF and CD, highlighting the promise of these techniques towards assessing long-term protein stability in neat formulations.Our findings have been published in a number of research papers and will appear in full in the PhD theses of the ESRs. We have also undertaken on-going and detailed analysis of how the fundamental research findings can lead to direct impact in industry in terms of exploitable findings. These have been shared across P&G research centres globally in short industry-focussed briefing documents. We summarise the main industry-relevant findings as:(1) Generation of a range of novel analytical protocols and “tool kits” that can be applied across a range of consumer goods areas.(2) New theoretical insights into controlling molecular migration have underpinned on-going UK Government and Industrially sponsored research with two other major industrial partners (value >€2m) from different sectors (AKZO Nobel, coatings) and Mondelez (foods). Seven researchers are employed on this follow-on project.(3) Predictive models for surfactant / dye interactions in aqueous solution and the relationship with deposition or removal from a range of common fabric surfaces.(4) A new method for probing enzyme stability in complex formulations helping to speed up product-innovation cycles.(5) Methods to follow reactive oxygen species formation and action in real time and under real operating conditions. These have been reapplied in several areas where an understanding of bleach function is required.In summary, we believe MICSED has been successful in its training, research and academia-industry collaboration goals. More details about the project are available at https://micsed.wordpress.com/.
