Felix A. Reifler of EMPA Laboratory for Advanced Fibers, St. Gallen (Switzerland) was using overjacketing extrusion to add a sheath or sheaths to a monofil core. The technology was essentially that used to apply insulation to fine copper wires. The main application appears to be applying an insulating sheath to silver-coated yarns for use in conductive textiles. An 80 micron polyester is plasma-sputter coated with silver and overcoated with 8 microns of thermoplastic PA12-based elastomer at 25 m/min. Dip-coating can also be used. PLA and PVA sheaths have also been tried. Adhesion of the sheath needs improving and the work continues.
Juan Esteban Diaz Gómez of NanoMyP Nanomateriales y Polímeros S.L., Armilla (Spain) has been spinning bicomponent nanofibres from annular nozzles where the core polymer solution can be a non-electrospinnable polymer. Hollow nanofibres, and liquid filled nanofibres (hydrophobic liquid inside a hydrophilic polymer) are also possible. They are now working on scaling up the process and further improving it with air-jets (“electroblowing”) or rotation (“Forcespinning™). “Smart materials with physicochemical properties tailored to customer needs” is now the subject of a new department. P&G, Unilever and Henkel were among the companies listed as customers of NanoMyP.