Halamish Hen Moshe, Trousil Jiří, Rak Dmytro, Knudsen Kenneth D, Pavlova Ewa, Nyström Bo, Štěpánek Petr, Sosnik Alejandro
Laboratory of Pharmaceutical Nanomaterials Science, Department of Materials Science and Engineering, Technion-Israel Institute of Technology, Haifa, Israel.
Institute of Macromolecular Chemistry, Czech Academy of Sciences, Prague, Czechia; Department of Analytical Chemistry, Charles University, Faculty of Science, Prague, Czechia.
J Colloid Interface Sci. 2019 Oct 1;553:512-523. doi: 10.1016/j.jcis.2019.06.047. Epub 2019 Jun 17.
Poly(vinyl alcohol)-g-poly(methyl methacrylate) (PVA-g-PMMA) amphiphilic copolymers self-assemble to form multi-micellar colloidal systems.
A PVA-g-PMMA copolymer containing 16-17% w/w of PMMA was synthesized by the free radical graft polymerization of methyl methacrylate on a PVA backbone by utilizing cerium(IV) ammonium nitrate as initiator and tetramethylethylenediamine (TEMED) as initiation activator. The aggregation behavior of the copolymer in water was comprehensively characterized by dynamic light scattering (DLS) and static light scattering (SLS), small angle neutron scattering (SANS), asymmetrical flow field-flow fractionation (A4F) and transmission electron microscopy (TEM). The colloidal stability before and after non-covalent crosslinking of PVA domains with boric acid was assessed by DLS. Finally, nanoparticles were nano spray-dried.
This copolymer self-assembles in water to form a complex nanostructure of low aggregation number particles (ca. 12-15 nm in diameter) that aggregate into larger ones with size ca. 60-80 nm, as determined by SANS and TEM. In addition, boric acid-crosslinking preserves the nanoparticle size, while conferring full physical stability under extreme dilution conditions. Nano spray-drying consolidates the crosslnking and enables the production of a dry flowing powder that upon re-dispersion in water regenerates the nanoparticles without major size changes.
聚乙烯醇接枝聚甲基丙烯酸甲酯（PVA-g-PMMA）两亲共聚物自组装形成多胶束胶体系统。
以硝酸铈铵为引发剂、四甲基乙二胺（TEMED）为引发活化剂，通过甲基丙烯酸甲酯在PVA主链上的自由基接枝聚合反应，合成了一种含16 - 17% w/w PMMA的PVA-g-PMMA共聚物。通过动态光散射（DLS）、静态光散射（SLS）、小角中子散射（SANS）、不对称流场-流分级（A4F）和透射电子显微镜（TEM）全面表征了该共聚物在水中的聚集行为。通过DLS评估了PVA域与硼酸非共价交联前后的胶体稳定性。最后，对纳米颗粒进行了纳米喷雾干燥。
该共聚物在水中自组装形成低聚集数颗粒（直径约12 - 15 nm）的复杂纳米结构，这些颗粒聚集形成更大的颗粒，尺寸约为60 - 80 nm，这由SANS和TEM测定。此外，硼酸交联可保持纳米颗粒的大小，同时在极端稀释条件下赋予完全的物理稳定性。纳米喷雾干燥巩固了交联作用，并能够生产出一种干燥的流动性粉末，该粉末重新分散在水中时可使纳米颗粒再生，且尺寸无重大变化。
