• 作者： Chen, Kai-Bin; Chang, Chien-Hsiang; Yang, Yu-Minet al.
• 中文摘要： 本研究乃探討在空氣/水界面之DPPC/正十六碳醇混合單分子層的熱力學行為及崩潰動力。利用電腦控制的膜壓測量裝置,量得在 15.degree.C,25.degree.C及37.degree.C下,DPPC/正十六碳醇混合單分子層的表面壓-每分子占據面積等溫線。分析結果顯示,在不同的表面壓及組成下,混合單分子層的分子占據面積與理想混合情形比較,皆呈現明顯的負偏差。由過剩混合自由能的變化,發現當DPPC的莫耳分率為0.5時,混合單分子層為最穩定的狀態。利用在崩潰點時,表面壓隨時間變化之鬆弛曲線的量測,探討此一混合單分子層在15-37.degree.C間的崩潰動力。結果顯示其崩潰過程可以利用一包括兩階段的成核及成長機制來描述。第一階段遵循Prout- Tompkins模式,第二階段則遵循類似二次反應的動力模式。
• 英文摘要： The thermodynamic behavior and collapse kinetics of mixed DPPC/n-hexadecanol monolayers at the air/water interface were studied. Surface pressure-area isotherms were obtained for mixed DPPC/n- hexadecanol monolayers at 15.degree.C, 25.degree.C, and 37.degree.C by using a computer-controlled film balance. The analysis indicated that, at all surface pressures and compositions, the areas of monolayers exhibited significant negative deviations from the ideal values. Excess free energy changes of mixing had been calculated and the most stable state of the mixed monolayer with x/sub DPPC/=0 .5 was found. The collapse kinetics of the mixed monolayers in the temperature range of 15-37.degree.C was investigated by the relaxation measurements of the surface pressure at the collapse point as a function of time. It was shown that the collapse process which occurred in two stages can be represented by a nucleation and growth mechanism. The first stage is described by the Prout-Tompkins law and the second stage is described by a second order kinetic law.
• 中文關鍵字： 空氣/水界面; 熱力學; 崩潰; 十六碳醇; 鬆馳; 界面活性劑
• 英文關鍵字： Air/Water Interface; Thermodynamics; Collapse; Hexadecanol; Relaxation; Surfactant