START - Self-Tuning Advanced Rheology Tool

Food industry, environmental monitoring, healthcare, diagnostic and micro-fluidic applications often require understanding the rheology of small volumes of simple and complex fluids. Although most of the processes affecting viscosity and density of fluids occur at microscopic length scales, traditional rheometers only allow investigating fluid properties in the bulk, leaving a gap of several order of magnitudes in length between what can be measured and what causes the observed changes in physical fluid properties. MEMS (Micro-Electro-Mechanical Systems) represent a really promising way to fill this gap, thanks to their ability of probing extremely small volumes of fluids. Traditionally, MEMS structures are excited using an external signal and their resonance frequency is used to track changes in fluid properties. However, the dynamics of such systems in a viscous fluid is not trivial and not fully controllable yet, often resulting in poor measurement signal-to-noise ratio that ultimately translates to poor accuracy and reliability.

The research proposed here aims to overcome this limitation of MEMS sensors, by creating a nonlinear self-excitation mechanism capable of automatically tracking the oscillation frequency of a microcantilever immersed in a viscous fluid. Changes in fluid properties translates to oscillations frequency shifts that can be easily tracked in real time without performing the frequency sweeps that are the main cause for poor accuracy in traditional externally excited MEMS sensors. This will allow for unprecedented resolution, ease of use and reliability of viscosity and density measurements on extremely small volumes of fluid.

The impact of the research proposed here can be broadly divided in three categories: industries, academic institutions and general public. The academic beneficiaries have already been described in the dedicated section, so here
only impact on industries and on general public will be briefly addressed.

Recent advancements in manufacturing, environmental monitoring and healthcare have created a market where very few players can operate due to the lack of suitable sensing platforms for these applications. The availability of the platform proposed here will open the door to new markets for UK industries, giving them an additional competitive edge in the global economic landscape. The research described in this proposal is aimed at laying down the foundations for the creation of a novel class of micro-sensors capable of reliably measuring fluid properties at the micro-scale, so there is a large potential for companies to pick the main research outcomes and move the technology towards commercialization in the near future. For this reason, preliminary contacts with relevant SMEs (DSoFt, MicruX and Elbatech) have already been established, but more potential partners will be actively contacted during and after the project, also with the support of Sensor City (one of the only four University Enterprise Zones in the country).

The creation of a novel sensor for measuring fluid properties at the micro-scale will also have a major impact on the society at large due to the impact on healthcare and manufacturing. For example, the availability of reliable point-of-care diagnostic devices will significantly improve the quality of life of the population and, at the same time, decrease the cost associated to healthcare. Similarly, being able to optimize advanced manufacturing techniques (e.g. 3D printing and additive manufacturing) will have a major impact on the manufacturing industry, as advanced platforms that at the moment are mostly relegated to research labs will become available to companies that will have more freedom in designing objects to be used in everyday life. Finally, completing the proposed research will also allow the PI (in his role as STEM Ambassador) to create demos aimed at increasing the public awareness of the current problems faced by healthcare and manufacturing technologies, and to use the proposed research as an inspiration for young pupils to stimulate their interest in STEM subjects.