The project is funded by a grant from the Swedish Foundation for Strategic Research (SSF) within their call for materials research, but the project is also linked up to other activities with financial support from other sources. The basis for the research activities is a close interaction between the participants each of which contributing with their unique competence. The participants are Chalmers University of Technology (Materials and Manufacturing Technology), Swerea-IVF, University of Borås (School of Engineering), Imego Institute and Russian Academy of Sciences (Moscow).
Short description of the content of the project
The overall objective of the work is to develop new lightweight and functional fibres, textiles and layers. All materials/components will be based on polymeric nanocomposites containing carbon nanotubes (CNTs), carbon black or carbon nanodiscs (CNDs). The intention is then to use these components in order to manufacture new or improved products. In the first place, commercially available nanoparticles will be used in the project. Due to their inherently good electrical conductivity, these particles are promising candidates for rendering polymeric materials electroactive. For example, the polymers, modified in a suitable manner, are likely to exhibit an enhanced piezoelectric effect, obtain a higher electrical conductivity that can be used in heating applications, changed light refracting properties (photorefraction) or improved electrical insulating performance which in turn can be implemented into new products. Such products will be in demand since they meet societal and consumer needs of lightweight and functional products related to living and recreational habitats, medical diagnosis, energy distribution efficiency, telecommunication, etc.
Knowledge and products emanating from the project can be used by Swedish industry, consumers and within university education. There are however several challenges. Issues to consider in order to achieve the objectives are for example related to separation and obtaining an adequate distribution of the nanoparticles in the matrix material. The structure of the particle network as well as its interaction with the polymer matrix constitute also critical factors. Hence experimental material science combined with computational physical chemistry is an important tool within the program. Several manufacturing techniques will be used and, if required, developed in order to achieve an improved or adequate particle dispersion, enhanced spinnability etc. In summary, the project is directed towards research and development of fibres and layers for smart materials/components/textiles, more specifically towards (i) new fibres/fabrics for lightweight and sensitive piezoelectric devices, (ii) melt-spun electrically conducting fibres for fabrics used in the automotive sector, (iii) new photorefractive films for high resolution imaging of human inner organs, (iv) improved telecommunication equipment and (v) improved insulating layers for high-voltage cables.
New results are emerging
The project has been running for a relatively short time, but several interesting results have already emerged. In her licentiate thesis from the beginning of this year, Anja Lund has described the prerequisites of manufacturing piezoelectric fibres based on the polymer poly(vinylidene fluoride) (PVDF). The work had the form of a collaboration between Swerea-IVF, University of Borås (School of Textiles) and Chalmers and the continuing activities also include the Imego Institute.
Shortly before the summer 2010, Martin Strååt from Swerea-IVF and Chalmers presented his Ph D thesis. Among other things, a technique for improving the spinnability of electrically conducting fibres containing carbon black was described; the restricted spinnability constitutes otherwise often a problem in this context. Martin Strååt also pointed to that, with a suitable heat treatment, the electrical conductivity of the manufactured fibres could be affected in a positive way. The processing technique employed in this case was based on spinning of bicomponent fibres which gave the required stability of the process. The photo below is a scanning electron micrograph of such a fibre with a sheath of polyamide and an electrically conducting core.
In addition, significant amounts of work have been devoted to clarify possible routes for dispersing carbon nanodiscs in a polymer matrix in order to obtain a sufficiently high conductivity. Preliminary results were presented at the ”Annual European Rheology Conference 2010” that took place at Chalmers in the beginning of April this year. The start and continuation of Lef-Tex also brings about a higher student involvement in this area of science and engineering, in the first place in the form of project work and M Sc theses. Several such activities are in progress or are planned for.
Further information about Lef-Tex can be obtained from the contact persons
Mikael Rigdahl and Rodney Rychwalski (Chalmers University of Technology), Bengt Hagström (Swerea-IVF), Kim Bolton (University of Borås) and Katrin Persson (Imego Institute)