Spectral barcode label for fighting illegal waste dumps

Illegal waste dumping is one of the biggest problem in environment protection. Shipments of waste are left in wastelands, forests or dumped into the sea. These activities are difficult to suppress because technologies available to track the waste, and hence the people responsible, are very limited.(1) This research focuses on developing an effective, low-cost way of labelling and detecting bulk waste material shipments. The technology is based on an easily retrievable material in the form of micro/nano magnets which are used as carrier for the spectral signal transducers (e.g. dyes and pigments). These pigment carrying magnetic particles are chemically and physically stable, can form unique spectral pattern to use as identifier tag. The project is divided into two parts: (i) the modification of the magnet particles with various dyes and pigments to form spectral codes (ii) the development of analytical technique for code readou

Spectral barcode label for fighting illegal waste dumps

Illegal waste dumping is one of the biggest problem in environment protection. Shipments of waste are left in wastelands, forests or dumped into the sea. These activities are difficult to suppress because technologies available to track the waste, and hence the people responsible, are very limited.(1) This research focuses on developing an effective, low-cost way of labelling and detecting bulk waste material shipments. The technology is based on an easily retrievable material in the form of micro/nano magnets which are used as carrier for the spectral signal transducers (e.g. dyes and pigments). These pigment carrying magnetic particles are chemically and physically stable, can form unique spectral pattern to use as identifier tag. The project is divided into two parts: (i) the modification of the magnet particles with various dyes and pigments to form spectral codes (ii) the development of analytical technique for code readout

Development of stimulus-responsive materials with improved performance characteristics for application as flow controllers in microfluidic platforms

This thesis investigates the synthesis and performance of various stimuli-responsive materials with the aim of obtaining a suitable material for flow control in microfluidic platforms. Therefore, at first a literature review is carried out to choose a material for investigation as well as to determine the limitations of current materials so that potential areas where improvements can be made are defined. The materials chosen are mainly based on thermo-responsive polymer N-isopropylacrylamide. Hence, in the beginning the polymerisation of this polymer is investigated in various phosphonium-based ionic liquids to afford novel ionogels with tuneable viscoelastic properties that can serve as robust platforms for incorporation of stimulus- responsive entities. Later these ionogels are demonstrated as a novel and suitable platform for incorporating functionalised magnetic particles to obtain a magneto-responsive, soft ionogel. Photo-responsive gels are obtained by incorporation of spiropyran molecule into the polymer matrix. Improvements to the existing formulations are made by incorporation poly-acid in the polymer chains which allows the material to be actuated without additional chemicals. Moreover, the speed of actuation is improved by engineering a porous microstructure of the gels. Finally, as a future outlook, recently discovered, thermo-responsive poly-ionic liquids are investigated as potential substrates for novel stimulus responsive poly-ionic liquid gels. All these materials have been investigated from the perspective of incorporation into microfluidic devices as soft polymeric valves

Integrating stimulus responsive materials and microfluidics – The key to next generation chemical sensors

New generations of chemical sensors require both innovative (evolutionary) engineering concepts and (revolutionary) breakthroughs in fundamental materials chemistry, such as the emergence of new types of stimuli responsive materials. Intensive research in those fields in recent years have brought interesting new concepts and designs for microfluidic flow control and sample handling that integrate high quality engineering with new materials. In this paper we review recent developments in this fascinating area of science, with particular emphasis on photoswitchable soft actuators and their incorporation into fluidic devices that are increasingly biomimetic in nature

Materials science: the key to revolutionary breakthroughs in micro-fluidic devices

In microfluidics, valves and pumps that can combine specifications like precise flow control, provision of precise reagent quantities, minimal sample carryover, and low-cost manufacture, while also being inherently compatible with microfluidic system fabrication, are beyond the current state of the art. Actuators in micro-fluidics made using stimuli-responsive materials are therefore of great interest as functional materials since actuation can be controlled without physical contact, offering improvements in versatility during manifold fabrication, and control of the actuation mechanism. Herein we review the potential use of novel approaches to valving and pumping based on stimuli-responsive polymers for controlling fluid movement within micro-fluidic channels. This has the potential to dramatically simplify the design, fabrication and cost of microfluidic systems. In particular, stimuli-responsive gels incorporating ionic liquids (ILs) produce so-called ‘ionogels’ that have many advantages over conventional materials. For example, through the tailoring of chemical and physical properties of ILs, robustness, acid/ base character, viscosity and other critical operational characteristics can be finely adjusted. Therefore, the characteristics of the ionogels can be tuned by simply changing the IL and so the actuation behaviour of micro-valves made from these novel materials can be more closely controlled