Janoszka Nicole, Azhdari Suna, Hils Christian, Coban Deniz, Schmalz Holger, Gröschel André H
Physical Chemistry, Center for Soft Nanoscience (SoN) and Center for Nanotechnology (CeNTech), University of Münster, Corrensstraße 28-30, 48149 Münster, Germany.
Macromolecular Chemistry II, University of Bayreuth, Universitätsstraße 30, 95440 Bayreuth, Germany.
Polymers (Basel). 2021 Dec 13;13(24):4358. doi: 10.3390/polym13244358.
The confinement assembly of block copolymers shows great potential regarding the formation of functional microparticles with compartmentalized structure. Although a large variety of block chemistries have already been used, less is known about microdomain degradation, which could lead to mesoporous microparticles with particularly complex morphologies for ABC triblock terpolymers. Here, we report on the formation of triblock terpolymer-based, multicompartment microparticles (MMs) and the selective degradation of domains into mesoporous microparticles. A series of polystyrene--polybutadiene--poly(-lactide) (PS--PB--PLA, SBL) triblock terpolymers was synthesized by a combination of anionic vinyl and ring-opening polymerization, which were transformed into microparticles through evaporation-induced confinement assembly. Despite different block compositions and the presence of a crystallizable PLA block, we mainly identified hexagonally packed cylinders with a PLA core and PB shell embedded in a PS matrix. Emulsions were prepared with (SPG) membranes leading to a narrow size distribution of the microparticles and control of the average particle diameter, ≈ 0.4 µm-1.8 µm. The core-shell cylinders lie parallel to the surface for particle diameters < 0.5 µm and progressively more perpendicular for larger particles > 0.8 µm as verified with scanning and transmission electron microscopy and particle cross-sections. Finally, the selective degradation of the PLA cylinders under basic conditions resulted in mesoporous microparticles with a pronounced surface roughness.
嵌段共聚物的受限组装在形成具有分隔结构的功能性微粒方面显示出巨大潜力。尽管已经使用了各种各样的嵌段化学，但对于微区降解的了解较少，而微区降解可能会导致ABC三嵌段三元共聚物形成具有特别复杂形态的介孔微粒。在此，我们报道了基于三嵌段三元共聚物的多隔室微粒（MMs）的形成以及微区选择性降解为介孔微粒的过程。通过阴离子乙烯基聚合和开环聚合相结合的方法合成了一系列聚苯乙烯-聚丁二烯-聚（-丙交酯）（PS-PB-PLA，SBL）三嵌段三元共聚物，并通过蒸发诱导受限组装将其转化为微粒。尽管存在不同的嵌段组成以及可结晶的PLA嵌段，但我们主要鉴定出具有PLA核和嵌入PS基质中的PB壳的六方堆积圆柱体。使用（SPG）膜制备乳液，导致微粒尺寸分布狭窄并可控制平均粒径，约为0.4 µm至1.8 µm。通过扫描电子显微镜和透射电子显微镜以及颗粒横截面验证，对于粒径<0.5 µm的颗粒，核壳圆柱体与表面平行，而对于粒径>0.8 µm的较大颗粒，核壳圆柱体则逐渐更垂直。最后，在碱性条件下PLA圆柱体的选择性降解产生了具有明显表面粗糙度的介孔微粒。
