利用表面力仪测量了在醋酸缓冲液中吸附壳聚糖的云母表面间表面力和黏附力,并获得了不同压力条件下的力-距离特性曲线.结果表明:在酸性环境下,壳聚糖能够吸附到云母表面并形成一层稳定的纳米薄膜层.当两云母表面相互靠近时,吸附壳聚糖纳米层会引起短程单调空间位阻力.两吸附壳聚糖的云母间黏附力随着载荷的变化而变化.在较大压力条件下,两吸附壳聚糖的云母表面间呈现很强的黏附作用.这种随压力变化的黏附特性主要是由于在高度受限环境下分子结构和氢键的重新排序所致.
The surface and adhesion forces between chitosan- coated mica surfaces in an acetic acid buffer solution were measured using a surface force apparatus (SFA). The force- distance profiles were obtained under different pressure conditions. It was found that the chitosan was adsorbed on the mica surface and formed a stable nanofilm under acid conditions. The adsorbed chitosan nanofilms induced a short- range monotonically steric force when two such surfaces came close in the acid buffer. The adhesion forces between the two chitosan-coated mica surfaces varied with the loads. Strong adhesion between the two chitosan-coated mica surfaces was observed at high pressure. Such pressure-dependent adhesion properties are most likely related to the molecular configurations and hydrogen bonds reordering under high confinement.