Habel Azza, Khan Ishrat M
Department of Chemistry, Clark Atlanta University Atlanta Georgia USA
RSC Adv. 2020 Oct 8;10(61):37358-37368. doi: 10.1039/d0ra04951d. eCollection 2020 Oct 7.
Hairy nanoparticles with polystyrene cores (PS cores) and poly(2-hydroxyethylmethacrylate) (PHEMA) shells were synthesized by combining living anionic polymerization and atom transfer radical polymerization (ATRP). The structural characterization was carried out by FT-IR and NMR spectroscopy (H NMR, C NMR, APT C NMR and H C HMQC). The thermal stability of the PS cores was not affected by grafting PHEMA on their surfaces. A differential scanning calorimetry (DSC) thermogram of the HNPs showed two distinct transition temperatures indicating microphase separation. Chiral HNPs were prepared by inducing chirality in the achiral HNPs by complexation with - or -mandelic acid. The circular dichroism (CD) spectroscopy of complexes of the HNPs/- or -mandelic acid indicated the formation of enantiomeric chiral structures. The self-assembled structures formed from the achiral HNPs show different surface morphologies, porous and zigzag, dependent on the solvents used. Blends of polystyrene functionalized with hydroxyl groups and PHEMA show different morphology and thermal properties compared with the core-shell HNP system. The chiral HNPs self-assembled into donut like structures or toroids with sizes in the range between 200 to 5000 nm. The study suggests that chirality can be utilized to develop interesting self-assembled structures.
通过结合活性阴离子聚合和原子转移自由基聚合（ATRP），合成了具有聚苯乙烯核（PS核）和聚（甲基丙烯酸2-羟乙酯）（PHEMA）壳的毛状纳米颗粒。通过傅里叶变换红外光谱（FT-IR）和核磁共振光谱（H NMR、C NMR、APT C NMR和H C HMQC）进行结构表征。PS核的热稳定性不受其表面接枝PHEMA的影响。毛状纳米颗粒的差示扫描量热法（DSC）热谱图显示出两个不同的转变温度，表明存在微相分离。通过与（-）-或（+）-扁桃酸络合，在手性非手性毛状纳米颗粒中引入手性，制备了手性毛状纳米颗粒。毛状纳米颗粒/（-）-或（+）-扁桃酸络合物的圆二色性（CD）光谱表明形成了对映体手性结构。由非手性毛状纳米颗粒形成的自组装结构根据所使用的溶剂显示出不同的表面形态，多孔和锯齿状。与核壳毛状纳米颗粒体系相比，羟基官能化的聚苯乙烯和PHEMA的共混物显示出不同的形态和热性能。手性毛状纳米颗粒自组装成尺寸在200至5000 nm之间的甜甜圈状结构或环面。该研究表明，手性可用于开发有趣的自组装结构。
