Preparation and properties of a novel remendable coating concept

Key properties of organic coatings, such as mechanical strength and solvent resistance, are greatly influenced by the structure of the polymeric binder. In general, a 3-dimensional polymeric network gives the best properties and therefore most performance coatings have a 3-dimensional network structure. However, 3-dimensional networks cannot easily be repaired. Through molecular design in combination with different synthetic routes, a series of new building blocks has been prepared that render conventional coating types thermally remendable. Damage can be repaired through thermally reversible cross-linking of the coating through reversible bond scission within these specially designed building blocks. At room temperature, a fully cross-linked network is present, whereas at elevated temperatures the cross-link density becomes much lower and the system becomes mouldable or low viscous. This self-healing concept was proven by various techniques. Both the thermal reversibility window and the final coating properties can be tuned by careful design of the system. © 2008 Elsevier B.V. All rights reserved

Roll-to-roll UV imprint lithography for flexible electronics

We propose a roll-to-roll UV imprint lithography tool as a way to pattern flexible PET foil with µm-resolution. As a way to overcome dimensional instability of the foil and its effect on overlay, a self-align approach was investigated, that permits to make several layers in a single lithography step. Flexible Ni-stamps were used, with a single level and with 2 levels. The stamps were fabricated on wafers using conventional optical lithography and Si etching. Thin Ni replica, both single and multilevel, were obtained by electroplating using a thickness of 50 µm. The flexible Ni stamps were attached on the main drum that is placed on a conventional roll-to-roll machine. Resist was dispensed drop by drop by valve-jet nozzle using solvent-free UV resist. The imprint speed was of 0.35 m/min, using a UV illumination of 2 W. Fifty imprints were made in a row, equivalent to 20 m foil length. High imprint quality was observed with good reproducibility. All features type were replicated, from 500 µm contact pads to 800 nm wide trenches and 1 µm wide lines. A resolution of 800 nm in 1 µm thick resist was obtained for single level imprint. Multi-level imprints (2 levels) show the same quality in replication with a resolution of 1 µm. © 2011 Elsevier B.V. All rights reserved

Novel imprinting techniques for fabrication of multilevel flexible electronics

We report a novel method to selectively deposit materials from solution into imprinted micro-capillaries. Dewetting of the solvent just outside the capillaries is balanced to evaporation inside the capillaries. In this way conductive u-wires can be self-assembled and self-aligned on flexible substrates opening the route to faster and cheaper plastic electronics

Reprint of "food-grade electrospinning of proteins"

Developing non-meat food products with an appealing structure is a challenge. In this study, we investigate the possibility to produce thin fibrils as building blocks for texturally interesting meat replacers. The technique applied is electrospinning - a technique which produces thin fibrils with a high aspect ratio. The spinning of proteins is notoriously difficult and most proteins cannot be spun under food-grade conditions. Only two proteins are known to spin under food-grade conditions. Zein was spun from ethanol, and gelatin from warm water. The current study looks into the possibility of using one of these proteins as a carrier for other proteins. With gelatin it was possible to electrospin a range of globular proteins, showing for the first time electrospinning of globular proteins in a food-grade way. Next steps in the progress towards industrial application are the fixation and alignment of the fibrillar structures and upscaling of the process. Industrial relevance The demand for high quality protein, that contains all essential amino acids, is growing. One of the challenges of alternative protein sources, such as plant storage protein, green leaf protein or insect protein, is to process it into a structurally appealing product. Fibrillar structure is acknowledged to play an essential role in giving texture and bite to protein products. Techniques for structuring include extrusion or shear cell texturizing. A technique on the nanoscale is not yet available. Such a technique can yield fibrils as building blocks for larger structures and in this way mimics meat. Electrospinning is one of the techniques that could fill that gap. © 2014 Elsevier Ltd