Composite multilayer films of the oxidized MWNTs and poly (ethyleneimine) (PEI) were fabricated through the layer-by-layer (LbL) assembly approach.

• 在电场力的作用下，凝胶内部可移动离子和溶液中离子发生定向移动，形成离子浓度梯度差，导致在凝胶两侧渗透压不平衡，使凝胶条向阴极弯曲。