Two orientations and photochromism of polyelectrolyte/bacteriorhodopsin alternative deposition multilayers  

作　　者：李美玲 李宝芳 江龙 Tapio Tussila Nikolai Tkachenko Helge Lemmetyinen 

机构地区：[1]Laboratory of Colloid and Interface, Center of Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, China [2]Institute of Materials Chemistry, Tampere University of Technology, FIN-33101 Tampere, Finland

出　　处：《Science China Chemistry》2000年第3期313-322,共10页中国科学（化学英文版）

摘　　要：A series of organized multilayers have been formed by the alternative adsorption of positively charged poly(dimethyldiallylammonium chloride) (PDAC) and purple membrane (PM) fragments in suspensions at pH = 4-11. Both UV-vis spectrophotometry and quartz crystal micro-balance (QCM) technique were used to monitor the deposition process of PDAC/bacteriorhodopsin (bR) multilayers, suggesting that PM fragments and PDAC are deposited alternatively on the substrate uniformly. Upon illumination, all these multilayers generate photovoltages with defined signs. The negative sign of photovoltage accompanying the formation ofM-state at pH < 7 indicates that the extracellular side of PM fragments is directed toward the substrate; and the positive sign at pH?7 indicates that the cytoplasmic side of PM fragments is directed toward the substrate. In addition, the long-lived multipleM-state has been observed in all multilayer films. Moreover,M-state at high pH, which shows the longer lifetime than that at low pH, decays into the ground state (B) completely in 30 min.A series of organized multilayers have been formed by the alternative adsorption of positively charged poly(dimethyldiallylammonium chloride) (PDAC) and purple membrane (PM) fragments in suspensions at pH = 4—11. Both UV-vis spectrophotometry and quartz crystal micro-balance (QCM) technique were used to monitor the deposition process of PDAC/bacteriorhodopsin (bR) multilayers, suggesting that PM fragments and PDAC are deposited alternatively on the substrate uniformly. Upon illumination, all these multilayers generate photovoltages with defined signs. The negative sign of photovoltage accompanying the formation of M-state at pH &lt;7 indicates that the extracellular side of PM fragments is directed toward the substrate; and the positive sign at pH≥7 indicates that the cytoplasmic side of PM fragments is directed toward the substrate. In addition, the long-lived multiple M-state has been observed in all multilayer films. Moreover, M-state at high pH, which shows the longer lifetime than that at low pH,

关 键 词：PURPLE membrane BACTERIORHODOPSIN PHOTOVOLTAGE UV-vis adsorption spectra. 

分 类 号：O657.3[理学—分析化学]