Observations of rubbed surfaces

Second Harmonic Surface Several molecular Molecular direction 

Generation (SHG) Water contact angle Surface layers Polrnty 

Ito et al. reported on grooves on a rubbed polyimide by observing RuO sputtered on a surface using scanning electron microscopy (SEM). These grooves had a spacing period of 30 nm and a depth of 1 nm. They concluded that such grooves 

Summarizing the AFM observations, fine grooves similar to the rubbing fibre structure, and nanoscale undulations in the background texture are observed on the rubbed polymer surfaces. 

To observe chemical changes in the rubbed surface, Lee and Paek measured the polarity of a rubbed surface by using water contact angle measurements, and discussed a correlation between the pretilt angle and the polarity of the rubbed surface [44,62]. The measurement method is illustrated in Fig. 2.2. 

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