In this study, a suitable route for the selective functionalization of the outer surface of MCM-48-type mesoporous silica nanoparticles (MSNs) and its impact on the physicochemical properties were investigated. The synthesis of MCM-48 nanoparticles with intact cubic ordered mesopore structure and functionalized outer particle surface was managed by postsynthetic and co-condensation modification routes with 3-methacryloxypropyltrimethoxy-silane (MPS). The results of FTIR, ²⁹Si and ¹³C NMR, thermogravimetric, and elemental analysis confirmed the successful silane surface grafting by both methods. The nitrogen sorption analysis showed the selective outer surface functionalization by the postsynthetic route for the synthesized MCM-48 nanoparticles containing the template still inside the pore channels and in the case of the co-condensation route via late addition of the silane precursors into the synthesis batch containing a fully grown silica. The solvent type in the former approach and silane addition time during the particle growth in the later route showed a significant impact on the silane content and site selective binding. The amount of grafted silane was determined by thermogravimetric and elemental analysis. It was found to increase using toluene in the postsynthetic modification route. The average particle size measured from SEM/TEM analysis ranges from 290 to 350 nm. The cubic ordered pore structure of the final silane grafted MSNs was fully preserved in both functionalization routes as corroborated from XRD analysis. In conclusion, MCM-48 nanoparticles selectively functionalized on the outer particle surface are favorable candidates for the subsequent site selective grafting reactions.

在这项研究中，研究了对MCM-48型介孔二氧化硅纳米粒子（MSNs）的外表面进行选择性官能化的合适途径及其对理化性质的影响。具有完整的立方有序介孔结构和功能化的外部粒子表面的MCM-48纳米粒子的合成是通过与3-甲基丙烯酰氧基丙基三甲氧基硅烷（MPS）的后合成和共缩合改性途径进行的。FTIR，²⁹ Si和^13的结果13 C NMR，热重和元素分析证实了两种方法均能成功进行硅烷表面接枝。氮吸附分析表明，对于合成的MCM-48纳米颗粒，其模板仍停留在孔道内，通过后合成途径进行选择性外表面官能化；对于共缩合途径，则通过将硅烷前体后期添加到合成批料中而进行共缩合含有完全生长的二氧化硅。前一种方法中的溶剂类型和后一种方法中的颗粒生长过程中的硅烷添加时间均对硅烷含量和位点选择性结合产生重大影响。通过热重和元素分析确定接枝硅烷的量。发现在合成后的修饰途径中使用甲苯会增加。通过SEM / TEM分析测得的平均粒度为290至350nm。最终的硅烷接枝MSN的立方有序孔结构在两种官能化路径中均得到了完全保留，这已通过XRD分析得到了证实。总之，在外部颗粒表面上选择性官能化的MCM-48纳米颗粒是随后的位点选择性接枝反应的理想候选物。