Kim, Jong Hun Cho, Hunyoung Yoon, Hongyeon Lee, Dooho Choi, Joong Il Jake Jung, Jong Hoon Kim, Sang Hoon Park, Jeong Young 2025-11-26T10:03:02Z 2025-11-26T10:03:02Z 2025-11-26 2025-11 0021-9606 https://pubs.kist.re.kr/handle/201004/153676 Water adsorption and phase transitions on NaCl surfaces before dissolution play a crucial role in understanding interfacial water–solid interactions. In this study, we employ variable-pressure scanning probe microscopy (SPM) to systematically investigate nanoscale morphological and tribological changes across a wide range of relative humidity (RH). At extremely low RH (<10−2%), water shows a strong affinity for Na+ ions, leading to increased friction, particularly at surface defects such as step edges. As RH increases to several tens of percent, this high-friction region expands across entire terrace areas. Below ∼40% RH, hydrated ion clusters form, locally reducing friction due to their liquid-like nature. Above ∼40% RH, these hydrated ion clusters disperse, resulting in a global decrease in surface friction. At higher RH levels, increased lubrication facilitates NaCl nanostructure movement, reducing pre-existing surface anisotropy and accelerating dissolution dynamics until deliquescence (∼75% RH). Our findings indicate that Cl− ion release is enhanced by water clusters, while strongly bonded Na+ ions remain exposed, acting as preferential sites for further adsorption. By utilizing SPM across a broad RH spectrum (10−7 to ∼75%), this study provides new insights into the fundamental nanoscale mechanisms governing water adsorption, phase changes, and dissolution at the NaCl–water interface. English American Institute of Physics Water–solid interactions on NaCl: Tracking adsorption to deliquescence with in situ scanning probe microscopy under a wide range of water vapor pressure Article 10.1063/5.0288046 1 The Journal of Chemical Physics, v.163, no.17 The Journal of Chemical Physics 163 17 N scie scopus 001612082600001 2-s2.0-105021069441 Chemistry, Physical Physics, Atomic, Molecular & Chemical Chemistry Physics Article ATOMIC-FORCE MICROSCOPY FUNDAMENTAL-ASPECTS PHASE-TRANSITIONS SILICON-OXIDE LATERAL FORCE DISSOLUTION NACL(100) FRICTION SURFACES BEHAVIOR