未变性胶原生物表面活性剂的表面张力及其表面吸附

Surface tension and surface absorption of undenatured collagen bio-surfactant

研究了一种未变性胶原生物表面活性剂(CBS)水溶液的表面张力和表面吸附性质。结果表明,CBS水溶液的表面张力随CBS浓度的增大而降低,最终趋于平缓,达到55.92 mN/m。在等电点附近,CBS表面静电荷降低,使其表面张力显著降低。在低温下,CBS溶液的表面活性较好,当温度继续升高(>35℃),由于变性作用,CBS溶液的表面张力急剧增大。CBS水溶液的吸附属于Langmiur型吸附,根据γ-lgC、Γ-C以及C/Γ-C拟合曲线计算得到饱和吸附量相似,分别为1.86×10-10,1.97×10-10和2.03×10-10 mol/cm2。吸附自由能为-3.53kJ/mol,表明其在标准状态下可以自发进行。

The surface tension and the surface absorption properties of undenatured collagen bio-surfactant (CBS)in aqueous solution were investigated in this paper.The results showed that with CBS concentration in-creased,the surface tension of CBS solution decreased firstly and then kept at constant;the equilibrium surface tension was 55.92 mN/m.Meanwhile,when the pH value of CBS solution was close to the isoelectric point of CBS,the net charge of CBS would decrease,which resulted in the lower surface tension.At lower temperature, CBS exhibited good surface activity;while at higher temperature (>35 ℃),the surface tension increased rapid-ly due to the denaturation.The absorption of CBS solution belonged to Langmiur-type absorption and the satu-rated absorption quantity were close according to theγ-lgC,Γ-C and C/Γ-C fitting curves,which were 1.86× 10-10 ,1.97×10-10 and 2.03×10-10 mol/cm2 ,respectively.Additionally,the absorption free energy of CBS was-3.53 kJ/mol,suggesting that the surface absorption of CBS in aqueous solution could be spontaneous at the standard condition.