Keis K, Huemmer C L, Kamath Y K
TRI/Princeton, Box 625, Princeton, NJ 08542, USA.
J Cosmet Sci. 2007 Mar-Apr;58(2):135-45.
In this paper sorption and desorption of water vapor on hair fibers treated with various oils is investigated, using a dynamic vapor sorption (DVS) apparatus. Results show lower "equilibrium" sorption of moisture for various oil-treated samples compared to the untreated sample. Coconut oil-treated hair had a higher regain than mineral oil-treated hair. Although treating the hair samples with oil reduced moisture pickup, a considerable amount of moisture vapor was still able to penetrate into hair fibers. Calculated hysteresis plots show that the samples treated with different oils have slightly higher moisture retention at low relative humidities compared to that of the untreated sample, which suggests a beneficial effect. The calculated moisture diffusion coefficients for oil-treated samples were much lower compared to the untreated hair fibers, suggesting that surface oil films and penetrated oil molecules form a diffusion barrier. A moisture diffusion model is discussed in terms of the possible role of fiber swelling on restrictive narrowing of the cell membrane complexes (CMCs), which form the diffusion pathways in the fiber. The effect of film thickness on moisture absorption and the reverting of the sorption isotherm to that of the untreated hair after removal of the oil film shows that oil film is the main resistance to moisture diffusion. The lowering of the diffusion coefficient of water vapor by oil films will slow the loss of moisture, an effect similar to "moisturization" of hair.
本文使用动态蒸汽吸附（DVS）仪器研究了水蒸气在经各种油处理的毛发纤维上的吸附和解吸情况。结果表明，与未处理的样品相比，各种油处理样品的水分“平衡”吸附量较低。椰子油处理的毛发回潮率高于矿物油处理的毛发。虽然用油处理毛发样品会减少水分吸收，但仍有相当数量的水蒸气能够渗透到毛发纤维中。计算得出的滞后曲线表明，与未处理的样品相比，不同油处理的样品在低相对湿度下的水分保留率略高，这表明存在有益效果。与未处理的毛发纤维相比，油处理样品的计算水分扩散系数要低得多，这表明表面油膜和渗透的油分子形成了扩散屏障。本文讨论了一个水分扩散模型，该模型涉及纤维膨胀对细胞膜复合物（CMC）狭窄的可能作用，而CMC构成了纤维中的扩散通道。膜厚度对水分吸收的影响以及去除油膜后吸附等温线恢复到未处理毛发的等温线，表明油膜是水分扩散的主要阻力。油膜降低水蒸气扩散系数会减缓水分流失，这种效果类似于毛发的“保湿”。
