Hydrophilic PEG-grafted liquid-like surface: sliding or spreading

Study on counterintuitive hydrophilic liquid-like surface (LLS) remain in a nascent stage despite its exceptional application potential in interfacial engineering. Here, inspired by the inherent wetting heterogeneity of mPEG-silane, for the first time we discover a dynamic wettability switching mechanism in PEG-grafted LLS through solvation-coupled mechanical regulation of PEG brush conformations. Ordered methoxy-terminated brushes enable water droplet sliding (θ ≈ 33°), while disordered ether-exposed configurations induce spreading (θ ≈ 4°). This conformational control allows unprecedented spatial decoupling of condensation modes (dropwise vs filmwise) on homogeneous surfaces, with sliding-state LLS showing increase nucleation efficiency versus PDMS-grafted LLS. Notably, spreading-state surface achieves ultrafast underwater oil detachment (< 0.8 s) through synergistic hydration from dense ether groups and low friction from flexible brushes. Our findings establish molecular conformation engineering as a paradigm for designing multifunctional LLS with applications spanning smart thermal management, microfluidic systems, and novel anti-oil fouling coatings.