Breath figure templated self-assembly of surface-acylated cellulose nanowhiskers confined as honeycomb films

Abstract The self-assembly of cellulose nanowhiskers (CNWs) in confined geometries provides a powerful method for the fabrication novel structures. Herein, ordered honeycomb microporous films were first prepared with surface-acylated CNWs (CNWs-SU) through breath figure method. Resulting showed highly porous order over large regions and iridescent color was only displayed by their rims, which is different from traditional dish-cast CNW showing whole area. This mainly due to condensation water droplets forming three-dimensional (3D) geometry, forced CNWs-SU self-assemble into cholesteric architectures geometry resulted rims after drying. mechanism further studied investigating critical influencing factors, primarily concentration CNW-SU suspensions, relative humidity atmosphere surface-attached moieties. In particular, suspensions 3 mg/mL at 75% preferentially formed uniform pores. Too low or too high concentrations are not preferable films. immobilized octadecane fluoroalkyl groups on surface strongly affected formation because higher hydrophobicity accompanying inhomogeneous droplets. work study interactions beyond planar solely structural colors open up interesting possibilities broad application photonic nanomaterials. Graphic abstract