Specimen charging, work function

A serious problem encountered in ion beam methods of analysis is that of specimen charging. Impact of energetic positive ions causes development of a positive charge on the surface of an insulator. This effect is especially prevalent in polymers, because they are usually excellent insulators. Table VII lists work functions for some typical polymers. It is questionable whether the term work function should be used for polymers, but the high value of these numbers shows the reason for the charging exhibited by polymers. 

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