For the apolar compounds, the derivatization was not necessary.

对极性化合物，不一定要进行这样衍化。

Moreover, the results of IR spectrum and apolar component of surface free energy showed that the alkyl chains of OTS tilted on the surface of PTW after the modification.

IR分析和色散分量测定表明，改性后OTS链倾斜在PTW表面。