Observation of a Chiral Hygroscopic Response at the Edge of Newsprint Sheets, 1999 International Paper Physics Conference Proceedings
Margaret Yu, Derek G. Gray
Reflected light microscopy was used to observe what happens to the cross-section of a newsprint sheet upon wetting. In addition to the expected sheet swelling, individual fibres at the edge of the sheet were observed to twist. The direction of twist was not random, but in a clockwise direction on wetting, and in a counterclockwise direction on drying. Large-perimeter, thick-walled fibres that are relatively free from contacts with surrounding fibrous material tend to twist more. The chiral twisting tendency results from the chiral helical structure of the wood cell wall and indicates that an additional mechanism may contribute to the response of paper sheets to wetting.
Observation of a Chiral Hygroscopic Response at the Edge of Newsprint Sheets, 1999 International Pap