The effects of softening agents on the wetting of textiles were investigated by measuring the capillary spreading of liquid as a function of time. The values of the exponent n during phase II of the capillary spreading of softened fabrics increased in comparison with those of unsoftened fabrics owing to the adsorption of the softening agent, which made the fiber surface more hydrophobic and produced a larger advancing contact angle of the fiber to the water (&thetas; A ). Based on experiments with DTAC as a softening agent for nylon, the following quantitative relationship was found between the value of the exponent n and the advancing contact angle of water (&thetas; A ): n = (4.62 X 10 -3 )&thetas; A , -0.001. From this, reasonable advancing contact angles were also estimated for other fabrics.

In a series of studies on the effects of finishes on textile wetting, the capillary spreading of a liquid drop in fabric was investigated by a photographic technique as a function of time, drop volume, and surface tension/viscosity ratio. The area covered by the spreading liquid was found to be expressed by an exponential equation. During phase I, when some of the liquid is on the fabric surface, the area of the spreading liquid is proportional to the square root of time, in accord with the Washburn equation. Phase II is when the liquid is contained within the fabric. For impermeable fibers, the exponents are in agreement with previously reported values. When the liquid diffuses into the fibers, the exponents decrease, increase, or remain essentially constant. The exponent of the spreading of n-decane increases with increasing hydrophobicity of the fibers. The exponents of rayon fabric exhibit anomalies caused by the geometry of rayon fibers.