The melts of a series of low molecular weight poly（ethylene oxide）（PEO） fractions on mica surfaces were studied by atomic force microscopy（AFM） and X-ray reflectivity（XRR） measurement.The PEO ultrathin films w...The melts of a series of low molecular weight poly（ethylene oxide）（PEO） fractions on mica surfaces were studied by atomic force microscopy（AFM） and X-ray reflectivity（XRR） measurement.The PEO ultrathin films were obtained via static dilute solution casting.Different from the melts of the PEO with both methoxyl（（—OCH3）） end groups that are dewetted on the mica surface,a pseudo-dewetting phenomenon of the PEO melts was observed when either one end group of the PEOs becomes hydroxyl（—OH） or both are hydroxyl groups.The wetting layer thicknesses of the pseudo-dewetted melts were measured to be 4.5～4.7 nm,independent on the molecular weight and the end groups of PEOs.However,the PEO melt droplets on the wetting layer varied from spherical caps with relatively high contact angle to irregular shapes with relatively low contact angle when increasing the molecular weight and the hydrophobicity of end groups of PEOs.展开更多
文摘The melts of a series of low molecular weight poly（ethylene oxide）（PEO） fractions on mica surfaces were studied by atomic force microscopy（AFM） and X-ray reflectivity（XRR） measurement.The PEO ultrathin films were obtained via static dilute solution casting.Different from the melts of the PEO with both methoxyl（（—OCH3）） end groups that are dewetted on the mica surface,a pseudo-dewetting phenomenon of the PEO melts was observed when either one end group of the PEOs becomes hydroxyl（—OH） or both are hydroxyl groups.The wetting layer thicknesses of the pseudo-dewetted melts were measured to be 4.5～4.7 nm,independent on the molecular weight and the end groups of PEOs.However,the PEO melt droplets on the wetting layer varied from spherical caps with relatively high contact angle to irregular shapes with relatively low contact angle when increasing the molecular weight and the hydrophobicity of end groups of PEOs.
