Supervised by Prof John de Mello (Chemistry, Imperial College) and Dr Philip Miller (Chemistry, Imperial College)

Polymerisation reactions undertaken in batch reactors are inherently difficult to control due to variability of such factors as temperature and concentration both throughout the reacting medium and over the duration of the reaction period. This typically leads to product polymer with poorly controlled average molecular weight and variable polydispersity – critical polymer parameters that have significant effects on processing and final materials properties. Polymer fractionation after polymerisation can be used to select a target molecular weight and reduce polydispersity, but it is a wasteful, expensive and time-consuming undertaking, and it is not generally feasible for high value electronic materials. New manufacturing methods capable of selectively synthesising polymers with desired properties – with minimal wastage – are urgently needed to overcome these problems.
Microreactors offer a complementary environment to conventional batch reactors, and have been shown to offer improved product selectivity for a wide range of chemical reactions, including polymerisations.

This project builds on significant expertise in microreactor technology at Imperial, encompassing both the design and fabrication of flow reactors and their subsequent application to areas such as sensing, small molecule synthesis, polymerisation and catalysis. This project is specifically focused on the development of methods for suppressing unwanted reaction side-products during polymerisation reactions to enable the direct synthesis of semiconducting and high dielectric insulating polymers with tightly specified physicochemical properties. This project aims to integrate a size-exclusion chromatography (SEC) instrument in-line with a microreactor to enable real-time monitoring of the average molecular weight and poly-dispersity of the polymerisation reactions. The effect of changes in variables (including, but not limited to, temperature, monomer concentration, ratio of monomers, catalyst concentration and solvent) will be investigated with in situ monitoring to determine the effect on electronic behaviour.

This project is well suited to a chemist or engineer wishing to gain hands-on experience of microreactors. According to the interests and background of the selected student, the project may focus on the development of novel microreactor hardware or the application of existing hardware to challenging chemistries that are hard to control using conventional flask chemistry. The opportunity exists for aspects of the project to be carried out collaboratively with AWE.

For more information, contact Prof John de Mello: j.demello@imperial.ac.uk

Funding confirmed

Supervised by Prof John de Mello (Chemistry, Imperial College) and Dr James Bannock (Chemistry, Imperial College)

Standard practice in plastic electronics research is to fabricate devices by hand – a slow, error-prone process with poor reproducibility. This project involves the development of an automated robotic system for fabricating organic devices, which will provide greater control, versatility, reproducibility and throughput than manual fabrication. The system will enable the fabrication of organic solar cells (OSCs), light-emitting diodes (OLEDs) and thin-film transistors (OTFTs) via spin-coating, and will comprise five main parts: (i) a solution carousel for preparing solutions of tuneable composition; (ii) a pipette gantry for collecting solutions from the carousel and dispensing them on a substrate; (iii) a spin-coater for casting uniform films; (iv) a gradient hot-stage for simultaneously annealing multiple substrates at different temperatures; and (v) an articulated arm for moving substrates between the spin-coater, hot-bench and evaporation mask. The system will be configured such that an evaporation mask will be loaded with blank substrates at the start of the fabrication run; and at the end of the run it will contain the same substrates in the same positions, now coated and ready for deposition of the top electrode. (This last step, which cannot easily be automated without significant additional expenditure, will take place in an evaporator housed inside a glove box).

The system will permit the fabrication of both single and multilayer devices; have the ability to deposit layers of tuneable composition from solvent mixtures; offer full control over the deposition and annealing conditions; be of a size that can (if necessary) be accommodated within a glove-box for the handling of air-sensitive materials; and will readily handle materials at the 10s of mg scale – an important consideration for new materials that are invariably in limited supply.

For more information, contact Prof John de Mello: j.demello@imperial.ac.uk

We regularly host UROP students during the summer months. If you are interested in doing a research placement in the group, please email John to find out about possible projects.

A list of recent project titles can be seen below. However we always prefer to match projects to individuals so, if you're interested in the kind of work we do, please get in contact and we'll see if we can come up with something that fits.

1. A robotic system for rapid fabrication of organic solar cells
2. Sizing of nanoparticles using a low cost multi-angle light scattering instrument
3. Highly emissive polymer nanospheres for bioanalysis
4. Analysis of chiral molecules using a novel flow-based polarimeter
5. Highly controlled synthesis of electronic materials in flow
6. Multistep chemistry using droplet-based flow reactors