Partial esterification of cellulose using acyl chlorides having 5 and 16 carbon atoms was performed in a swelling medium to produce cellulosic esters with two different degrees of substitution (DS = 0.15 and 0.45). The effects of this treatment on the surface energy, on the water uptake, and on the acido-basic character of the cellulose were studied by inverse gas chromatography and thermogravimetric analysis. The attaching of alkyl chains to the surface of cellulose reduces its acidic character and its hydrophilicity and the DS required for such an effect depends on the chain length.