Preparation and Chirality Investigation of Electrospun Nanofibers from Optically Active Helical Substituted Polyacetylenes

Chiral fibers exist widely in nature; however, only limited success has been achieved in imitating them for preparing artificial continuous chiral fibers. This results in a big scientific challenge to deeply investigate chiral materials from viewpoints of macroscopic chirality and practical uses. The present paper reports the first protocol for preparing optically active nanofibers derived from chiral helical polymers via the electrospinning process, using a helical substituted polyacetylene as a model. Scanning electron microscopy (SEM) images demonstrate the electrospun nanofibers possessing regular morphology, uniform dimension, and the desired continuity. Circular dichroism (CD) spectra show that the nanofibers have remarkable optical activity, which has originated in the predominantly one-handed helical polymer chains. To further improve the properties of the nanofibers, substrates were used for preparing composite nanofibers, which also show the anticipated optical activity. The present work opens up an unprecedented, versatile, and powerful platform for preparing chiral polymer nanofibers with potential chiral applications as chiral sensors and membranes, among others.