疏水高分子介导可动芯SiO2杂化纳米粒子的仿生合成

在疏水高分子胶体模板——含氟丙烯酸酯(FA)共聚物乳胶粒中引入能够介导SiO2原位沉积的聚胺催化活性点-甲基丙烯酰氧乙基三甲基氯化铵(DMC),以四甲氧基硅烷(TMOS)为硅源,在环境条件下可控合成了核壳型FA共聚物/SiO2杂化纳米粒子.高温煅烧除去聚合物核质,可得到中空的SiO2纳米粒子,结合FTIR、EDX、TGA以及XPS等表征数据印证了SiO2的沉积主要发生在聚合物模板的表面.进一步考察了反应条件,如聚胺功能单体DMC的浓度、TMOS的浓度以及反应时间对SiO2杂化纳米粒子的形貌与组成的影响.实验结果表明增加DMC或者TMOS的浓度,适当延长反应时间,均可增加SiO2粒子的沉积速率,导致SiO2壳层的厚度增加,并且杂化粒子的形貌由凹陷多褶皱的核壳结构向可动芯结构转变.由于FA共聚物模板的强疏水性,增加有机核层和无机壳层间的不相容排斥,最终导致核壳层间空腔的形成,得到含可动芯的核壳型SiO2杂化粒子.

BIOMIMETIC SYNTHESIS OF HYBRID SiO_2 NANOPARTICLES WITH A MOBILE CORE TEMPLATED BY HYDROPHOBIC COPOLYMER

A series of well-defined hydrophobic copolymers latexes of fluorinated acrylate(FA) with 2-methacrylatoethyl trimethyl ammonium chloride(DMC) were synthesized as potential colloidal templates,and then the core-shell FA copolymer —SiO2 hybrid nanoparticles(NPs) with a mobile core were synthesized via deposition of tetramethyl orthosilicate(TMOS) in aqueous media at room temperature,allowing the formation of hollow-structured silica NPs by subsequent calcinations.No experimental evidence was found for nontemplated silica formation,which indicated that silica deposition occurred exclusively in the latex surface and formed FA copolymer-SiO2 hybrid NPs,which was confirmed by the combination of FTIR,EDX,TGA and XPS determination.Studies from TEM and TGA indicated that the morphology and composition of the resulted SiO2 hybrid nanoparticles could be well controlled by adjusting the DMC concentration,the amount of TMOS and the deposition time.Higher DMC concentration,higher level of TMOS amount or longer deposition time produced the FA copolymer-SiO2 hybrid nanoparticles with more enriched SiO2 content and thicker SiO2 shell.Moreover,the morphology of the core-shell hybrid nanoparticles with dented wrinkled surface turned to regular spherical nanoparticles with a mobile core after SiO2 deposition.These new core-shell FA copolymer-SiO2 hybrid nanoparticles with a mobile core and corresponding hollow-structured silica nanoparticles would have potential applications for high-performance encapsulation and delivery of drugs,pigments and the active organic molecules.