AMS-regulated One-pot Synthesis Of Functional Raspberry-like And Snowman-like Microspheres Via Dispersion Polymerization

Raspberry-like and snowman-like microspheres were widely used because of their unique morphologies.For the past few years many preparation methods were developed but most of them suffered from tedious procedures and froward conditions,therefore,a simple synthetic route needs to be developed.Dispersion polymerization is a simple way to synthesize functional microspheres,but it will affect monodispersion of the obtained particles when vast cross-linking agent added at the beginning of reaction.So retarder is used to adjust cross-linking progress,or cross-linking agent can be added after nucleation period,in this way monodispersed microspheres can be obtained.However,most reported methods were used to prepare spherical particles,few of them mentioned how to prepare anisotropic microspheres.Our group developed a one-pot synthesis of various functional anisotropic microspheres,which was realized by adjusting degree of crosslinking and degree of swelling of the dynamic growth particles formed via dispersion polymerization.Based on previous researches and consider the features of a-AMS,we present a method that utilize retardation of AMS to adjust crosslinking reaction rate of DVB during the adding process of one-pot and one step or two steps method,in this way degree of crosslinking and degree of swelling of growth particles can be regulated and raspberry/snowman-like microspheres can be obtained.To our best knowledge,there is no report to prepare functional anisotropic microspheres via AMS-regulated dispersion polymerization with the properties of simple operation method,easy-controlled reaction conditions and vast preparation of anisotropic microspheres with functional groups on the surface.The main works in this paper are listed below:1.One-step dispersion polymerization:In the mixture of methanol and water(MeOH/H2O = 6/4),dispersion polymerization was proceeded using styrene(St),AMS and NaSS as monomers,azodiisobutyronitrile(AIBN)as initiator,DVB as cross-linking agent,different amount of AIBN was added during the process and monodispersed raspberry-like microspheres could be obtained.2.Two-steps dispersion polymerization:In the mixture of methanol and water(MeOH/H2O=6/4),dispersion polymerization was proceeded using St,NaSS as monomers,AIBN as initiator,DVB,AMS and AIBN were added at different time to form snowman-like microspheres.During the process,morphologies were observed by SEM and TEM,convert ratio and gel content were measured,the formation conditions of snowman microspheres were studied,the dosage of DVB,dosage of AIBN and time of adding AIBN were also investigated to figure out the relative influence of convert ratio of monomers,surface roughness of particles,the amount and size of embossment.3.Taking advantage of easy-depolymerization feature of AMS,re-initiation of AMS-contained polymer microspheres under UV was studied.4.Functionalization of functional raspberry-like particles:Sulfhydryl was introduced via click polymerization,or after ester-functionalization dopamine was added to introduce hydroxy and surface functionalization of microspheres will be realized;In-situ reduction method was used to coordinate silver,polymer/silver nanoparticles composite microsphere were prepared.Besides,the amount of complexing silver affected by different complexing solvent,click monomers and reaction conditions were studied and conditions to coordinate silver was optimized.