Enantioselective membranes prepared by electrospinning of cellulose tris(3,5-dimethylphenyl carbamate) having various degrees of polymerization: effect of the DP on the morphology

Cellulose phenyl carbamates such as cellulose tris(3,5-dimethylphenyl carbamate) (CDMPC) are known to act as chiral selectors when they are coated or immobilized on silica gels that are packed in the columns for high-performance liquid chromatography (HPLC). Previously, we reported a proof of concept of enantioselective membrane filtration using a nonwoven membrane prepared by electrospinning of the CDMPC synthesized from microcrystalline cellulose Avicel((R)). In the present work, TECHNOCEL (R) cellulose fiber samples derived from hardwood are functionalized to synthesize CDMPCs having higher and different degrees of polymerization. The length and width of the cellulose fiber samples are characterized using a MorFi image analyzer. The obtained CDMPCs are electrospun to form nanofibrous membranes and their morphology is studied in relation to the electrospinning process parameters, the degrees of polymerization of the CDMPCs, and their solution concentrations. Liquid-liquid permeation experiments of a racemic compound, (R,S)-1-(1-naphthyl)ethanol, through the CDMPC membranes demonstrate preferable permeation of the (S)-enantiomer. This is supported by theoretical simulations using a molecular docking model that indicates stronger hydrogen bonding and pi-pi interactions with higher binding energy between CDMPC and the (R)-enantiomer than the (S)-enantiomer.