The working hypothesis for this research project is that it is possible to develop a new functional polymer printing process for the direct application of conductive polymer onto textiles. We will use the basic extrusion technology that is currently applied in 3D printing. Thus the aim is also expanding the knowledge and knowhow base of 3D printing and make this technology applicable for deposition of functional polymers on textiles in such a way that process parameters are clearly understood, and pre-defined final product specifications can be met. Thus the challenge is to apply conductive tracks with a simple one step process that fits the current textile production processes. This means that investigating polymer deposition onto textiles of bio based polymers like PLA, doped with carbon could be a versatile route to achieving economic and sustainable conducting textiles. If the mechanism underlying the bonding of doped PLA with textiles can be controlled for processing then a new route to achieving conductive grids would be opened.Paper written by the Saxion chair Smart Functional Materials and The Unversity of Twente for and accepted by the Autex Conference 2013 (22-24 May 2013, Dresden, Germany).
MULTIFILE
With a market demand for low cost, easy to produce, flexible and portable applications in healthcare, energy, biomedical or electronics markets, large research programs are initiated to develop new technologies to provide this demand with new innovative ideas. One of these fast developing technologies is organic printed electronics. As the term printed electronics implies, functional materials are printed via, e.g. inkjet, flexo or gravure printing techniques, on to a substrate material. Applications are, among others, organic light emitting diodes (OLED), sensors and Lab-on-a-chip devices. For all these applications, in some way, the interaction of fluids with the substrate is of great importance. The most used substrate materials for these low-cost devices are (coated) paper or plastic. Plastic substrates have a relatively low surface energy which frequently leads to poor wetting and/or poor adhesion of the fluids on the substrates during printing and/ or post-processing. Plasma technology has had a long history in treating materials in order to improve wetting or promote adhesion. The µPlasma patterning tool described in this thesis combines a digital inkjet printing platform with an atmospheric dielectric barrier discharge plasma tool. Thus enabling selective and local plasma treatment, at atmospheric pressure, of substrates without the use of any masking materials. In this thesis, we show that dependent on the gas composition the substrate surface can either be functionalized, thus increasing its surface energy, or material can be deposited on the surface, lowering its surface energy. Through XPS and ATR-FTIR analysis of the treated (polymer) substrate surfaces, chemical modification of the surface structure was confirmed. The chemical modification and wetting properties of the treated substrates remained present for at least one month after storage. Localized changes in wettability through µPlasma patterning were obtained with a resolution of 300µm. Next to the control of wettability of an ink on a substrate in printed electronics is the interaction of ink droplets with themselves of importance. In printing applications, coalescence of droplets is standard practice as consecutive droplets are printed onto, or close to each other. Understanding the behaviour of these droplets upon coalescence is therefore important, especially when the ink droplets are of different composition and/or volume. For droplets of equal volume, it was found that dye transport across the coalescence bridge could be fully described by diffusion only. This is as expected, as due to the droplet symmetry on either side of the bridge, the convective flows towards the bridge are of equal size but opposite in direction. For droplets of unequal volume, the symmetry across the bridge is no longer present. Experimental analysis of these merging droplets show that in the early stages of coalescence a convective flow from the small to large droplet is present. Also, a smaller convective flow of shorter duration from the large into the small droplet was identified. The origin of this flow might be due to the presence of vortices along the interface of the bridge, due to the strong transverse flow to open the bridge. To conclude, three potential applications were showcased. In the first application we used µPlasma patterning to create hydrophilic patterns on hydrophobic dodecyl-trichlorosilane (DTS) covered glass. Capillaries for a Lab-on-a-chip device were successfully created by placing two µPlasma patterned glass slides on top of each other separated by scotch tape. In the second application we showcased the production of a RFID tag via inkjet printing. Functional RFID-tags on paper were created via inkjet printing of silver nanoparticle ink connected to an integrated circuit. The optimal operating frequency of the produced tags is in the range of 860-865 MHz, making them usable for the European market, although the small working range of 1 m needs further improvement. Lastly, we showed the production of a chemresistor based gas sensor. In house synthesised polyemeraldine salt (PANi) was coated by hand on top of inkjet printed silver electrodes. The sensor proved to be equally sensitive to ethanol and water vapour, reducing its selectivity in detecting changes in gas composition.
This study aims to provide an in-depth characterization of the intelligent behaviour exhibited by structures fabricated using fused deposition modelling (FDM) printing technology. The primary objective is to understand the variability in the shape-morphing behaviour of additively manufactured PLA structures. A comprehensive analysis is conducted to shed light on the impact of various factors on shape transformation, encompassing both working and printing parameters. To establish the relationship between the printing and working parameters with the shape morphing characteristics, the experimental procedure employs Taguchi's method design of experiments. Notably, the study quantitatively reveals the extent of these parameters' impact on the characteristics.
Currently, many novel innovative materials and manufacturing methods are developed in order to help businesses for improving their performance, developing new products, and also implement more sustainability into their current processes. For this purpose, additive manufacturing (AM) technology has been very successful in the fabrication of complex shape products, that cannot be manufactured by conventional approaches, and also using novel high-performance materials with more sustainable aspects. The application of bioplastics and biopolymers is growing fast in the 3D printing industry. Since they are good alternatives to petrochemical products that have negative impacts on environments, therefore, many research studies have been exploring and developing new biopolymers and 3D printing techniques for the fabrication of fully biobased products. In particular, 3D printing of smart biopolymers has attracted much attention due to the specific functionalities of the fabricated products. They have a unique ability to recover their original shape from a significant plastic deformation when a particular stimulus, like temperature, is applied. Therefore, the application of smart biopolymers in the 3D printing process gives an additional dimension (time) to this technology, called four-dimensional (4D) printing, and it highlights the promise for further development of 4D printing in the design and fabrication of smart structures and products. This performance in combination with specific complex designs, such as sandwich structures, allows the production of for example impact-resistant, stress-absorber panels, lightweight products for sporting goods, automotive, or many other applications. In this study, an experimental approach will be applied to fabricate a suitable biopolymer with a shape memory behavior and also investigate the impact of design and operational parameters on the functionality of 4D printed sandwich structures, especially, stress absorption rate and shape recovery behavior.
In het project 'Circular Material Testing for 3DP' (CMT) willen partners HB3D en Bambooder samen met de Hogeschool van Amsterdam (HvA) de geschiktheid beoordelen van verschillende circulaire materialen voor 3D-printen (3DP) met industriële robots, om een verdere verduurzaming van deze technologie te ondersteunen. Verschillende materialen zullen worden onderzocht en vergeleken op hun optimale printomstandigheden. Er zal een beoordelingsprotocol worden ontwikkeld om de materialen te beoordelen. Dit protocol introduceert a) specifiek ontworpen 3D-objecten die kunnen helpen bij het demonstreren en vergelijken van printcapaciteiten; b) specifieke tests om de mechanische eigenschappen van het materiaal te bepalen en c) circulaire experimenten om de 3DP-levenscyclus van deze materiaalstromen te controleren (d.w.z. de mogelijkheid om opnieuw te printen met het materiaal van een oude print). Alle resultaten zullen op een uniforme en uitgebreide manier worden gepresenteerd om de norm te stellen voor toekomstige tests en om ontwerpers / producenten te ondersteunen bij het selecteren van materialen voor Robot 3DP-toepassingen. Onderzoek wordt uitgevoerd door de Digital Production Research Group van het Centre of Expertise Urban Technology, samen met bovengenoemde partners, die leveranciers zijn van biobased plastics (Bambooder) en Robot 3DP toepassen (HB3D). De ontwikkelde tests zullen worden toegepast op standaard, fossiel polymeermateriaal, en vervolgens op twee nieuwe, circulaire materialen voor 3DP, geleverd door Bambooder en HB3D (die circulaire printmaterialen van DSM gaat leveren). Het project werkt toe naar een standaard beoordelingsprotocol (inclusief circulariteit) dat de acceptatie van nieuwe materialen voor 3DP kan vergemakkelijken. Een dergelijk protocol biedt materiaaleigenaren nieuwe kansen om hun specifieke afvalstromen te upcyclen. CMT is een belangrijke en gewenste stap richting industrieel 3D-printen met circulaire materialen, dat bijdraagt aan de ontwikkeling van slimme industrie en circulaire economie, beide relevant voor de maatschappelijke uitdagingen zoals opgenomen in de nationale Kennis- en Innovatieagenda voor wetenschap en technologie.
A feeling of worry, anxiety, loneliness and anticipation are commonplace in both medical and non-medical arenas such as elderly care. An innovative solution such as the ‘simple and effective’ comfyhand would offer better patient care and improved care efficiency with a high chance of long-term, economic efficiency. ComfyHand is a start-up in the healthcare sector that aims to develop sustainable products to improve patient wellbeing in healthcare settings. It does this by emulating the experience of holding a hand which gives the person comfort and support in moments where real human contact is not possible. Right now the comfyhand is in the development phase, working on several prototypes for test trials in elderly care and hospitals. In this project we want to explore the use of 3D printing for producing a comfyhand. Desired properties for the prototype include optimal heat transfer, softness, regulation of sweat, durability and sustainability. The goal of this study is to develop a prototype to test in a trial with patients within Envida, a care centre. The trial itself is out of scope of this project. This proposal focuses on researching the material of choice and the processability. Building on knowledge gained in a previous Kiem GoChem project and a Use Case (Shape3Dup) of a currently running Raak MKB project (Enlighten) on 3D printing of breast prostheses, several materials, designs and printing parameters will be tested.
