If you’ve purchased a new pair of prescription glasses in the last twenty years, chances are you were given a cleaning “cloth” to keep them in pristine condition.  Actually, “cloth” is not best description since the material doesn’t contain any cotton - the word that most often comes to mind when we say “cloth”.  Better to call it something else.
 

You wouldn’t know just by looking at it, but the cleaning “fabric” that came with your new glasses incorporates a special textile made up of strands of either polyester and nylon or polyester alone with a unique structural composition.  The microfibers that comprise the fabric are extraordinarily small.  It appears that this cleaning fabric incorporates some rather unusual technology to give you a clearer vision of the world through those new glasses.

 

The microfibers in that fabric are so small that 9000 meters of a single microfiber strand would weigh less than one gram! Since one denier is the weight in grams of 9000 meters of a single strand, it is not surprising that  microfiber materials are referred to as “microdenier” materials[1]. While this in itself may be fascinating to a textile engineer, we tend to think of the diameters of the strands as a measure of size.  It is not surprising then, to learn that the strand diameter of a microdenier is approximately 10 - 15 µm, about 1/5 the diameter of a human hair.  Teeny tiny. 

 

The microdenier strands are comprised of a central core of polyester often shaped in the form of a six-vaned asterisk if you were to look at the strand end on.  Fitted into the openings of the vanes of the central polyester core are six individual wedge-shaped nylon or polyester strands.  Other constructions could use an 8- or 16-vaned central core with wedges of nylon or polyester strands. As mentioned above, the entire assembly – the central vaned core with accompanying wedges - measures 10-15 µm in diameter.  The diagram below for a six-vaned core explains it better than the description above.

 

 

 

In Part II, we will describe the use of such microdeniers to fabricate cleanroom wipers and the advantages that the microdeniers have in removing surface contaminants.

 


[1] Note that this term is  descriptive, but not  scientifically accurate.  The prefix “micro” refers to 10-6 (one millionth).  Microdenier fabrics do not weigh one millionth of a denier.  In this case, “micro” is used in a more liberal sense. meaning ”less than one”.  Not scientifically accurate, perhaps, but more appealing than “subdenier”.