Classical density functional theory is used to study the general aspects of wetting phenomena occurring in nonpolar neutral molecule system near a flat solid wall. Current cognitions of the wetting behavior are looked at, validated, corrected and extended. Several new observations are made: (i) the present theoretical calculations suggest that over a broad range of the surface potential parameters the pre-wetting transition temperature interval significantly reduces with the wetting temperature, and at the same time a continuous and monotonous increase of the wetting temperature is induced by decreasing the surface potential range and/or relative strength of surface atom versus fluid atom interaction. (ii) There exist lower limit values of both the surface potential range and the relative strength, below which the wetting transition is impossible. (iv) The present theoretical calculations confirm an experimentally found no adsorption occurring in weak surface potential substrates all the way to the relevant critical temperature by showing the impossibility of wetting at bulk critical temperature and its surroundings; moreover, the calculations extend the experimental observation to a wider parameter domain by indicating that the impossibility is not only unique feature of the weak surface potential substrates, but also applies to all situations of the surface potential range and relative strength. (v) With progressive increase of the relative strength and/or progressive decrease of the temperature, the interfacial phase behavior becomes increasingly complex: the (pre-)wetting transition and layering transition (which can be thermodynamically stable, metastable or even situated at supersaturated vapor phase) are intertwined closely; this challenges the popular knowledge that there is no (pre-)wetting for strong substrates for which the pre-wetting is replaced by the layering transitions.

经典的密度泛函理论用于研究在平坦固体壁附近的非极性中性分子系统中发生的润湿现象的一般方面。查看，验证，纠正和扩展了对润湿行为的当前认知。进行了几项新的观察：（i）当前的理论计算表明，在较宽的表面电势参数范围内，预润湿转变温度区间随润湿温度而显着减小，而同时连续且单调地增加了温度。润湿温度是通过降低表面原子范围和/或表面原子相对于流体原子相互作用的相对强度来诱导的。（ii）存在表面电位范围和相对强度的下限值，在该下限值下不可能发生润湿转变。（iv）目前的理论计算结果表明，在体临界温度及其周围环境中不可能润湿，从而在实验上未发现在弱表面电位的基材上一直到相关的临界温度都没有吸附现象；此外，通过表明不可能性不仅是弱表面电势基底的独特特征，而且还适用于表面电势范围和相对强度的所有情况，计算将实验观察扩展到更宽的参数域。（v）随着相对强度的逐渐增加和/或温度的逐渐降低，界面相行为变得越来越复杂：（预）润湿转变和分层转变（可以是热力学稳定的，亚稳态或什至处于过饱和气相）紧密缠绕在一起; 这挑战了普遍的知识，即对于牢固的基材没有（预）润湿，对于这些基材而言，预润湿已被分层过渡所替代。