Printing Technology

Listen

The Printing Technology group is led by Patrick Gane. The group focuses on developing printed microfluidic devices using functionalised coating pigments, binders and hydrophobic inks, printing nano and microscale patterns for analyte control and light interactive devices. Rheological properties of complex micro and nanoparticulate suspension systems forms a key competence.

Research Strategy

The research group is active in developing highly porous functional coatings to meet growing technology challenges in which liquid-surface interactions drive analytical tools, diagnostics, pharmaceutical analysis and security features. Designing the rheological and particle interaction properties of complex suspensions provides the backdrop to the research strategy, additionally providing the opportunity for a multidisciplinary role within the department’s Bioproducts and biosystems research activities.

Highly Porous Custom Coatings

We develop highly porous coatings utilising a functionalised calcium carbonate pigment (FCC). The coatings can be customised by using pigments with different specific surface areas and particle sizes, together with charge modifiers and binders, such as microfibrillated cellulose (MFC). Our research topics include studying the wicking speed of liquids in contact with porous coating media, and the use of custom surface treatments to generate a platform for chromatographic separation to provide material separation and reactive microfluidic analytical devices.

Functionalised pigment coatings

The FCC pigment has a bimodal pore size distribution, which enables fast absorption by high capillarity in intr-particle pores and high permeability through inter-particle voids.

New applications

New applications for functionalised calcium carbonate (FCC) based coatings include microfluidic devices such as paper-based reaction assays and enzymatic assays as well as medical diagnosis, environmental monitoring and laboratory research tools.

Wicking speed and chromatographic separation of components

We have developed methods to test the wicking speed and chromatographic properties of the coated samples. For example, this video shows the separation of water and the anionic amaranth colorant on slightly cationic FCC coating in a horizontal test set-up (12x speed).

Functional Inkjet Printing

We investigate inkjet printing as a method to functionalise porous materials to produce analytical platforms. Custom inks are being developed to modify localised pore surface chemistries to control flow of aqueous liquids (by selective hydrophobisation) or concentrate/separate ionic molecules (by surface charge modification). As part of the research, methodologies to evaluate the ink/substrate interaction and effect of functionalisation are also being developed.

Fabrication of hydrophobic patterns

Test patterns are fabricated by printing hydrophobic inks on porous subtrates with a DMP-2831 inkjet printer.

Inkjet-printed reaction arrays

The hydrophobising agent amount needed to form a waterfproof barrier depends on the properties of the coatings. The effectivity of the barrier can be controlled by varying the hydrophobising agent, drop spacing and number of ink layers.

Changing the charge of the coating by inkjet printing

Inkjet printing can be used to effect the desired transfer and separation of compounds in the coatings by changing the charge of the coating regionally. For example, this video shows the concentration of anionic tartrazine colourant (yellow) from wicking aqueous solution on printed cationic polyelectrolyte regions.

Rheologically induced material interactions

The ability to induce designed inter-species adsorption of particulate material within a gel suspension using controlled rheological conditions is a breakthrough technology centred on the emerging application of micro and nanocellulose in nanofunctional devices and processes. The adsorption of nanoparticles onto nanofibrils of cellulose whilst maintaining a gel-like condition is a discovery of particular significance in a wide range of applications, both in medical and analytical research, and in industry. One such potential application is the analysis of nanoparticles in suspension using gellant microfluidic devices, including a potential solution to the challenge of dewatering nanomaterials.