Conventional artificial nanochannels have obvious shortcomings in permeability regulation and environmental friendliness, which challenge their practical applications. Polymer-modified switchable nanochannels are considered as a potential solution owing to their high chemoselectivity and controllability. Herein, systematic dissipative particle dynamics (DPD) simulations are performed to investigate the conformational transition and stretching behavior of polysulfobetaine in the presence of an explicit solvent. Polysulfobetaine is one kind of zwitterion polymer with a responsive property to the change of salt ion concentration, which is grafted onto the internal surface of the nanochannel to achieve the "open-close-open" switch. The simulation results indicate that the grafting ratio of 1.52 chains/r_c² (r_c is a reduced unit of length, 1 r_c = 0.857 nm) and salt ion concentration of 5 wt% NaCl are optimal parameters to achieve the "open-close-open" functionality. Specifically, salt ions promote the closure of nanochannels via regulating the electrostatic attraction of the polymer chain in z-direction and the excluded volume effect caused by conservative forces. On the other hand, the competition mechanism between electrostatic force and conservative force is revealed, i.e. at low salt concentration, electrostatic force dominates and close the nanochannel; With salt ions concentration increasing, conservative force gradually exceeds electrostatic force, and becomes the dominant force and reopens the nanochannel. This study provides some molecular insights for the design of stimulus-responsive artificial nanochannels, which may find application in the exploitation of natural gas hydrates, such as temporary plugging agents in well drilling for gas hydrate reservoirs.

传统的人工纳米通道在渗透性调节和环境友好性方面存在明显的缺点，这对其实际应用提出了挑战。聚合物修饰的可切换纳米通道由于其高化学选择性和可控性而被认为是一种潜在的解决方案。在此，进行了系统的耗散粒子动力学（DPD）模拟，以研究聚磺基甜菜碱的构象转变和拉伸行为明确溶剂的存在。聚磺基甜菜碱是一种对盐离子浓度变化具有响应特性的两性离子聚合物，将其接枝到纳米通道的内表面上以实现“开-关-开”通道。转变。模拟结果表明，接枝率为1.52链/r_c²（r_c 是长度的简化单位，1 r_c = 0.857 nm) 和盐离子浓度5 wt% NaCl 是实现“开-关-开”效果的最佳参数。功能。具体来说，盐离子通过调节聚合物链在z方向上的静电吸引力以及保守力引起的排除体积效应来促进纳米通道的闭合。另一方面，揭示了静电力与保守力之间的竞争机制，即在低盐浓度下，静电力占主导地位并关闭纳米通道；随着盐离子浓度的增加，保守力逐渐超过静电力，成为主导力并重新打开纳米通道。这项研究为刺激响应型人工纳米通道的设计提供了一些分子见解，可能会在天然气水合物的开采中得到应用，例如天然气水合物储层钻井中的临时封堵剂。