An overhead view (bottom) shows cylindrical block-coploymer structures, consisting of a central polymer (blue) linked to a surrounding polymer (red). An atomic-force microscope image (center), shows the densely packed cylinders, dark in the center, with the varying height of the surface beneath them visible as alternating lighter and darker stripes. The side view diagram (top) shows how the cylinders arrange themselves along the ridges of the crystalline facets.
From the Register, all this technogoodness, of course, is useless if it remains cooped up a university lab. Xu’s not worried. “The beauty of the method we developed is that it takes from processes already in use in the industry, so it will be very easy to incorporate into the production line with little cost.”
Significant hurdles remain before this technique will hit the market, of course – not the least being the development of magnetic or optical heads with the capability of reading a three-nanometer domain.
Self-assembling block copolymers, formed by two chemically different polymers linked together, have the potential to vastly improve the properties and manufacturing processes of nanostructured materials. Using crystals as a template, researchers have formed perfect arrays of nanoscopic block-copolymer structures extending over several square centimeters.
The achievement of a 10-terabit array of block copolymers formed in a single step on oriented crystal facets offers immediate practical promise. By treating the film of polymer structures with a solvent, the core polymer at the center of each cylinder is easily removed. The resulting thin film is a nanometer-sized sieve of a kind that could be used as a template for data storage or nanowires or other ordered nanoscopic structures for use in electronics or other devices.
Says Xu, “All the elements came together in this method – a good idea, a leader like Tom Russell with 20 years of experience in the field, a really good postdoc like Soojin Park to direct the experiment – and it worked. This one is going to make it to the market.”
Xu’s group is working with synthetic peptides and artificial proteins, as well as with block copolymers and nanoparticles, to build new functional materials based on molecules designed with novel electronic, photonic, and biological properties.
Generating laterally ordered, ultradense, macroscopic arrays of nanoscopic elements will revolutionize the microelectronic and storage industries. We used faceted surfaces of commercially available sapphire wafers to guide the self-assembly of block copolymer microdomains into oriented arrays with quasi–long-range crystalline order over arbitrarily large wafer surfaces. Ordered arrays of cylindrical microdomains 3 nanometers in diameter, with areal densities in excess of 10 terabits per square inch, were produced. The sawtoothed substrate topography provides directional guidance to the self-assembly of the block copolymer, which is tolerant of surface defects, such as dislocations. The lateral ordering and lattice orientation of the single-grain arrays of microdomains are maintained over the entire surface. The approach described is parallel, applicable to different substrates and block copolymers, and opens a versatile route toward ultrahigh-density systems.