MOISTURE IN TEXTILES 



237 



ANGSTROM UNITS 

 Fig. 6 — The cellulose unit cell or crystallite structure. 



4. Hair Swelling due to Fibril Surface Moisture 

 The diameter of the water molecule is reported as 3.8 AU. The 

 surfaces of adjacent fibrils along growth ring boundaries must be 

 separated at least 2 X 3.8 = 7.6 AU when a monomolecular layer of 

 water is present on each contiguous surface. This corresponds to a 

 total increase in hair diameter of 33 X 2 X 7.6 = 500 AU. The 

 percentage diameter increase in the hair is: 



(500/125000) X 100 = 0.4%. 



