Beeswax‐Modified Starch–Cellulose Composites with Superhydrophobic and Self‐Cleaning Capability

Abstract

Starch‐based materials have been proposed as the alternatives to plastic tableware and packaging materials; however, starch materials suffer from poor wear resistance because of their hydrophilicity. Therefore, it is essential to prepare starch composites with hydrophobic functionalization especially using fluorine‐free compounds. In this study, superhydrophobic starch–cellulose composites are fabricated by using polyethyleneimine (PEI) as the adhesive layer and beeswax as the functionalized layer. The superhydrophobicity (contact angle: 152°) is achieved by building the rough surface and low surface energy of beeswax. Meanwhile, polyethyleneimine tightly connects the beeswax coating and the starch composites by hydrogen bonding, and the surface remains superhydrophobic even after 200 s of water impact. The water/moisture absorption reduced significantly (>30%) after beeswax functionalization thanks to the increased hydrophobicity while the mechanical strength keeps the same (≈22 MPa) compared with the unfunctionalized sample. The self‐cleaning study on various types of liquid drinks (milk, cola, coffee, tea) on the superhydrohobic starch composites demonstrates efficient repellence to the fluids and retains the superhydrophobicity upon different liquid. The durable and biodegradable starch–cellulose composites with excellent self‐cleaning and antifouling performance provide the methodological basis for developing next‐generation green packaging materials over common plastics.

Superhydrophobic coatings with environmentally friendly materials

“…Beeswax density of 1.1 mg cm −2 was the correct value to maintain superhydrophobicity having contact angles above 150° and a sliding angle of 6°. The coatings indicated resistance to immersion of water for a long time and showed the ability to repel liquid foods [37].…”