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Foggingon transparent surfaces such as goggles causes a seriesof hazards to users. To fabricate antifogging and low-haze transparentrenewable polymer materials, intrinsic hydrophilicity with high wateradsorption capability of thermoplastic starch （TPS） had been adopted.Strikingly, when benzoic acid （BA） was blended with thermoplasticstarch （TPS-BA）, the haze of TPS-BA was only 7.8% when it sufferedthe cold and warm method of antifogging measurement with 87% transmittance.Simultaneously, TPS-BA achieved an 18 mm inhibition zone for Staphylococcus aureus. To reveal the antifoggingmechanism of TPS-BA films, the surficial and interior structure featureswere evaluated by three-dimensional optical scanner, scanning electronmicroscopy （SEM）, contact angle testing, small-angle X-ray scattering（SAXS）, X-ray diffraction （XRD）, temperature-dependent Fourier transforminfrared （FTIR）, dynamic mechanical analysis （DMA）, and so on. Theincorporation of BA resulted in the roughness （Rq）, water contact angle （WCA）, and crystallinity of the TPS-BAfilm decreasing from 6.5 to 0.68 μm, 65.1 to 39.9°, and13.6 to 6.3%, respectively. The amorphous matrix and smooth surfacereduced the scattered light, allowing the TPS-BA film to achieve lowhaze performance and high transmittance. Importantly, the diversifiedand weakened hydrogen bonds formed among starch, BA, and glycerolcould inhibit the formation of starch crystalline regions and allowedhydroxyl groups to quickly bond with water. Thus, when TPS-BA is placedin a high-humidity surrounding, an “expressway” is constructedfor water molecules diffusing into the TPS-BA matrix. This novel low-haze,antifogging, sustainable, and facilely fabricated TPS with antibacterialproperties is a promising candidate in disposable medical gogglesto fight against COVID-19. Animproved intrinsic hydrophilic thermoplastic starch wasdeveloped with excellent antifogging performance, which shows potentialto replace petroleum-based polymers for sustainable development.
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