Copolymers Create More Space For Hard Disks
November 13, 2012

Self-Assembling Copolymers Can Increase Hard Drive Capacity

Michael Harper for — Your Universe Online

With a little chemistry and research, a team of engineers at the University of Texas at Austin has developed a method which may increase the amount of capacity a hard drive can store fivefold. Their research has been published in this week´s edition of the journal Science and will even be put to a real-world test by HGST, a leader in disk drive technology.

Disk drive technology has hit a virtual wall as of late, limiting how much data can be stored. The actual drives could get bigger, but these days everyone´s looking for smaller and faster, not larger and slower. As it stands, information is written on the spinning plates of the disks in the drive. The head zips back and forth to pick up this information and more information can be packed onto these plates if it´s pushed closer together. The problem here, of course, is if the data is placed too closely together, the head can confuse two different pieces or read them at the same time. This could cause the data to become corrupt and unstable.

“The industry is now at about a terabit of information per square inch,” explained C. Grant Wilson, professor of chemistry and biochemistry in the College of Natural Sciences who co-authored the paper.

“If we moved the dots much closer together with the current method, they would begin to flip spontaneously now and then, and the archival properties of hard disk drives would be lost. Then you´re in a world of trouble. Can you imagine if one day your bank account info just changed spontaneously?”

These dots could be moved closer to one another and made more stable if the bits of data aren´t separated by magnetic material which tends to jumble the data for the reader. The team decided to look towards a substance called block copolymers. These self-organizing substances can assemble themselves into a series of very precise patterns of dots and lines and, with a little help, these copolymers can even line up in a precise manner of the manufacturer´s choosing. This means the bits of data can be packed closely to one another without the magnetic material interfering with the way this data is read.

The process of getting this material to act in a certain way (called directed self-assembly, or DSA) was first conceived at the University of Wisconsin and MIT.

Engineers from these universities had only successfully managed to shrink the data and arrange it in a way to double the capacity of a hard disk drive. Wilson and his team have been able to not only squeeze out even more storage space using this technology, they´ve also found a way to get these copolymers to arrange themselves on the surface more quickly than ever before. Using their own synthesized block copolymers, the team has been able to form them into the right patterns in only 30 seconds.

“I am kind of amazed that our students have been able to do what they´ve done,” said Wilson. “When we started, for instance, I was hoping that we could get the processing time under 48 hours. We´re now down to about 30 seconds. I´m not even sure how it is possible to do it that fast. It doesn´t seem reasonable, but once in a while you get lucky.”

The team has even devised a top coat for the block copolymers which allows the substance to continue self-assembling.

While using a self-assembling copolymer to squeeze more space out of a hard drive sounds elaborate, other methods likely take the cake.

HGST has also said they´ll begin experimenting with hermetically sealed hard drives filled with helium in order to reduce drag on the rapidly spinning plates of a hard drive.