Preparation And Patterning Printing Technology Of Polystyrene Fluorescent Nanoparticles

The synthesis and research of fluorescent nanomaterials has always been one of the research areas of particular interest to the industry.The polymer conjugated compound of the polymer matrix can achieve high brightness,spectrally adjustable,low biotoxicity and high biocompatibility,so we chose this material for research.Polystyrene(PS)fluorescent microspheres are a new type of functional material with excellent properties,which can impart optical properties and chemical stability to microspheres through a series of functional reactions.This gives PS fluorescent nanoparticles some unique recognition properties.PS fluorescent microspheres have been widely used in the field of information recognition.One of the important applications is the application of spectrally adjustable aspe cts based on fluorescence resonance energy transfer.The popularity of two-dimensional(2D)barcodes plays a key role in simplifying people’s daily lives(such as identification,sign-in,etc.).As the popularity of bar codes has increased,related problem s have gradually emerged.The most urgent and representative problem is decryption and forgery,which can lead to serious information leakage.These problems are due to the visible properties of the barcode.Therefore,we want to invent a way to store info rmation invisible barcodes with low cost,anti-counterfeiting and protection of personal privacy.Contrary to visible barcodes that are easily accessible,we designed and manufactured an invisible fluorescent printing ink to prevent privacy violations and sensitive information leakage.The information printed by this ink is not visible in daylight but visible under UV light.This invisible printing ink provides a broad prospect for solving the problem of information leakage.We used microemulsion methods to make PS fluorescent nanoparticles.The size of the nanoparticles can be adjusted from 40 nm to 200 nm.The method uses PS to add a toluene solution of a fluorescent dye(Anthracene,Coumarin 6 or polyfluorene fluorescent dye)as an oil phase,and a sodium dodecyl sulfate(SDS)solution as an aqueous phase,which is emulsified to obtain a PS fluorescent nanoparticle.In the emulsification process,we quantitatively change the mass fraction,quantity and proportion of fluorescent dyes.Energy transfer occurs between the dye molecules in the PS fluorescent nanoparticles,and the emission spectrum of the emulsion also changes.We further verified the energy transfer between dye molecules in PS fluorescent nanoparticles by detecting fluorescence lifetime and cal culating F?ster resonance energy transfer(FRET)efficiency.Using FRET changes under different parameters,we chose PS fluorescent nanoparticles that are not visible in the daily environment and are printed on a non-fluorescent paper base in the form of a 2D code.The information contained in the invisible pattern can only be identified by the excitation of ultraviolet light for the purpose of protecting personal information.From the industrial point of view,we replaced the Anthracene and Coumarin 6 with two polyfluorene-based polymer conjugated compound fluorescent dyes.The new dye has a higher absorption rate and better light stability.The improved fluorescent emulsion and polyethylene glycol were mixed at different volume fractions.Invisible printing inks are made by adjusting printing parameters such as viscosity coefficient,surface tension and stability of the mixture.This invisible printing ink has a printing accuracy of 30 microns and is capable of accurately printing 2D barcodes patterns and identifying information.At the same time,we have also achieved a variety of print patterns.To further confirm the feasibility of the everyday application of invisible printing inks,we printed 2D barcodes containing patient information on a medical wristband.The fluorescent QR barcodes are not visible in the natural environment,but is read under 365 nm UV excitation,which provides a viable solution for protecting personal privacy and reduces the possibility of forgery.As we have shown,this technology,as a platform for patterned encryption technology,has great potential and application prospects in anti-counterfeiting tags,information encryption and delivery.