Preparation And Application Of Aromatic Nanocapsules With Sustained Release Property

Fragrance is beneficial for human beings to beautify,relieve stress,relax muscles,and so on.The fragrance retention time is very short due to the low boiling point and high volatility of the aroma molecules.Therefore,how to protect fragrance is very important in order to delay the release rate.This thesis covers the preparation and application of aromatic nanocapsules,utilizing silica as wall material to protect aroma molecules from fast evaporation to achieve the sustained-release property of the aromatic nanocapsules as well as the aromatic fabrics.(1)Hollow mesoporous silica nanosphere(HMSN)was firstly prepared by hard-template method.Then aromatic nanocapsules were prepared by loading lemon essential oil into HMSN.The loading conditions were optimized via orthogonal test by investigating the influences of temperature,time and volume fraction of essential oil on the loading capacity.The morphology of nanoparticles was characterized by SEM and TEM.The loading capacity and sustained-release rate were investigated by UV-visible-near infrared light spectrophotometer.The results show that the loading capacity of nanocapsules was as high as 85.8% under optimal conditions,and the amount of the essential oil released was only 7.9% after placement of 6 days at temperature of 20?,promising a fairly good slowrelease property.Utilizing the roughening effect of the aromatic nanocapsules coated on the cotton fibers,aromatic superhydrophobic fabrics were easily obtained through hydrophobization.And investigation shows that superhydrophobicity enhanced the sustained-release effect of fragrance on the fabrics.(2)Lavender nanocapsules were prepared by sol-gel method and applied onto cotton fabrics.The emulsion nano-droplets were obtained by pre-emulsification and high speed emulsification of the mixed solution,which includes lavender essential oil,tetraethoxysilane,hexadecyl trimethyl ammonium bromide,and hexadecane.The as-prepared emulsion was transferred to the round bottom flask followed by the hydrolysis and condensation reactions of TEOS at 40? for 24 h under constant stirring of 400 rpm to form lavender nanocapsules.The effects of emulsification time,speed,emulsifier content and wall core mass ratio on morphology,loading capacity and particle size of nanoncapsules were investigated.The morphology and size of nanocapsules were characterized by TEM.UVvisible-near Infrared Light Spectrophotometer was used to determine the loading capacity and slow-release rate.Results show that the loading capacity of lavender nanocapsules is up to 58.7%,and the amount of the essential oil released was only 19.6% after placement of 15 days at temperature of 20?.Aromatic superhydrophobic fabric was also prepared by treating fabric with the as-obtained lavender nanocapsules as roughening structures and hydrophobic binding agent of AG-950 as low surface energy material.The obtained fabric possessed excellent self-cleaning and anti-fouling properties which enhanced the sustained-release effect of fragrance.