Study On POM-based Functional Materials And Their Assembly Process In Solution

Polyoxometalates-based functional materials have widely recievedattention in the past decades. In this paper, we select two water-solublefunctional polymers, that is potential anti-tumoral poly（2-hydroxyl-3-（2-hydroxyethylamino） propyl methacrylate）（PGEA） and water-solubleanti-bacterial chitosan （carboxymethyl chitosan, CMC）, and fourpolyoxometalates （POMs） to prepare a series of organic-inorganic hybridassembly materials. A number of spectroscopic technologies are utillilized tomonitor the solution behavior of the assembly process.First, the water-soluble, low-toxicity functional polymer PGEA with lotsof secondary amine gruops in the side chains which can be protonated in theaqueous solution is assembled with the typical preyssler type（NH₄）₁₄[NaP₅W₃₀O₁₁₀]31H₂O(denoted as P₅W₃₀) and the[NH₃ⁱPr]₆[Mo₇O₂₄]·3H₂O（denoted as Mo₇） to obtain a range of organic-inorganic hybrid functional materials. Several spectroscopictechnologies such as FT-IR,¹H NMR, ICP, UV-Vis are used to characterize thePGEA/POMs hybrid assembly materials. Then, DLS and Zeta potentialmeasurements are chosen to monitor the assembly process and determine thecharge raio at which the solution net charge becomes stable and close to zero.The mophologies of the bybrid assembly obtained by SEM and TEM areconfirmed to be core-shell structure. Finally, MTT method reveals that the IC₅₀values of the PGEA/POMs hybrid materials are much lower than those of thepure PGEA or POMs, which shows that the cooperative effect between PGEAand POMs enhances the anti-tumor activities of the PGEA/POMs hybridassembly materials.Second, further selection of one water-soluble derivative of the chitosanwith non-toxicity, high quantity existence in the nature, good properties ofbiocompatible and biodegradable which has plenty of the primary amines isdevloped to assemble with two kinds of POMs (including sandwich typeNa₉[GdW₁₀O₃₆]·32H₂O (denoted as GdW₁₀) and lacunary Wells-Dawson typeK₁₀[-P₂W₁₇O₆₁]·20H₂O (denoted as P₂W₁₇)) to prepare two kinds of hybridmaterials. Their properties are studied by FT-IR, UV-Vis, powder XRD andTG-DSC etc. DLS and Zeta potential measurements are used to monitor theself-assembly process and the sensitivity to the different physiological pHconditions. In order to study the self-assembly process of the bybrid materialsin the aqueous solution for a long time, SEM and TEM offer strong results directly. Different ratios may play an important role in the final self-assemblymophorlogy for a relatively long time.