Controlling polymer structure
Polymers are very large molecules and materials made up of smaller subunits called monomers. Some are natural like rubber or cellulose. Others, including the plastics polyethylene, polypropylene and poly(ethylene terephthalate), are synthetic or engineered. Engineered polymers have become ubiquitous, changing sectors from construction and electronics to packaging and transport. In addition to their interesting properties, they can be produced with well-established low-cost and high-throughput manufacturing techniques. They are also easily integrated with chemical and biological functionalities, increasing the possibilities for tailor-made functionalities and putting biocompatibility, bioactivity and eco-friendliness within reach. The EU-funded training project CONDPOLYBLENDORD (Controlling the order of functional polymers and their corresponding blends) addressed the issue of controlled crystallisation that is required to ensure functionality is achieved. The project focused on organic semiconductors, an emerging class of materials already being used in organic light-emitting diodes. Scientists employed high-surface area additives to increase the volume of nucleation sites in the host material, facilitating control of crystallite size. This was the first-ever attempt to use so-called nucleation agents to control the morphology of conducting polymers and polymer-fullerene blends, and its success has spurred a flurry of new research. Intensive work is under way to optimise processing protocols and characterise the relationship between microstructure and charge transport in these materials to support their exploitation. Project results are widely applicable and expected to have unprecedented impact on functional materials such as ferroelectrics, magnetic organics and nanomaterials for a variety of sectors. In this way, CONDPOLYBLENDORD outcomes could lead to streamlined design and development of specialty products for a global market with important socioeconomic impact on the EU and its citizens.
Keywords
Polymer, organic, electronics, crystallisation, semiconductor, nucleation