The mass discarding face masks has caused severe environmental problems during and after the COVID-19 pandemic.To reduce waste and minimize environmental impact,we present a new face mask featuring selfcharging extend...The mass discarding face masks has caused severe environmental problems during and after the COVID-19 pandemic.To reduce waste and minimize environmental impact,we present a new face mask featuring selfcharging extended service time and fully biodegradable materials.To extend the effective service time,we need to supplement the lost electric charge of the electret layer of face masks,for which task we propose to use the piezoelectric effect and generate electricity from breathing motions.However,existing piezoelectric materials are either toxic,impermeable,rigid,costly,or non-degradable.We synthesize a fully biodegradable piezoelectric membrane composed of polyvinyl alcohol(PVA)and glycine(GLY)via the electrospinning process.Parameters are accurately controlled to ensure that glycine crystallizes into a highly piezoelectricβphase during electrospinning and enables piezoelectric responses of the filter membrane.Tested with the standard 0.3μm particles,face masks made of the PVA-GLY membrane show an outstanding filtration efficiency of 97%,which remains stable over at least 10 h of high-concentration continuous filtration.Furthermore,we demonstrated the biodegradability of PVA-GLY masks,which can degrade completely within a few weeks,compared to commonly used surgical masks requiring over thirty years to be decomposed.展开更多
基金supported by General Research Grants (GRF Project No. 11212021 and No. 11210822) from the Research Grants Council of the Hong Kong Special Administrative Regionthe Innovation and Technology Fund (Project No. ITS/065/20GHP/096/19SZ) from Innovation and Technology Commission of Hong Kong Special Administrative Region
文摘The mass discarding face masks has caused severe environmental problems during and after the COVID-19 pandemic.To reduce waste and minimize environmental impact,we present a new face mask featuring selfcharging extended service time and fully biodegradable materials.To extend the effective service time,we need to supplement the lost electric charge of the electret layer of face masks,for which task we propose to use the piezoelectric effect and generate electricity from breathing motions.However,existing piezoelectric materials are either toxic,impermeable,rigid,costly,or non-degradable.We synthesize a fully biodegradable piezoelectric membrane composed of polyvinyl alcohol(PVA)and glycine(GLY)via the electrospinning process.Parameters are accurately controlled to ensure that glycine crystallizes into a highly piezoelectricβphase during electrospinning and enables piezoelectric responses of the filter membrane.Tested with the standard 0.3μm particles,face masks made of the PVA-GLY membrane show an outstanding filtration efficiency of 97%,which remains stable over at least 10 h of high-concentration continuous filtration.Furthermore,we demonstrated the biodegradability of PVA-GLY masks,which can degrade completely within a few weeks,compared to commonly used surgical masks requiring over thirty years to be decomposed.
