Study On Self-assembly Of Amphiphilic Molecules And Functional Materials Based On Hyperbranched Poly (Ether Amine)

Hyperbranched polymers(HBPs)are the macromolecule with highly branched and spherical-like topology.HBPs exhibit low molecular entanglement,low melting/solution viscosity,weak mechanical strength,high solubility,highly reactive functional groups,excellent capacity of encapsulation for guest molecules,and unusual self-assembly behaviors.HBPs are a very good self-assembled precursor.They can form multi-dimensional and multi-sized supramolecular structures by solution or interface selfassembly.By controlling the hydrophilicity of the hyperbranched polymer backbone and terminal functional groups,it is possible to regulate the shape of the assemblies.The rich microscopic nanostructures expand the scope of research on supramolecular self-assembly.At the same time,the high-reaction sites of hyperbranched polymers can be functionalized to prepare materials with special functions,which are very potential in water treatment,drug release and delivery,sensors,high-performance coatings,high-efficiency polymer additives,etc.Hyperbranched poly(ether amine)(hPEA)are a class of hyperbranched polymers prepared by the reaction of amino groups with epoxy groups.These polymers have abundant reactive functional groups and three-dimensional topologies.The amphiphilic molecule of hPEA is a kind of excellent assembly precursor by adjusting the characteristics of the skeleton and the terminal functional group to construct a self-assembled structure with various morphology and regularity.At the same time,macroscopically,there is a very special hydrophilicity and hydrogen bonding between hyperbranched polyetheramine and water,and high-density functional groups can interact with various contaminating molecules,so it can be used by various methods to fabricate environmental-friendly material having a selective adsorption separation effect.Therefore,in this paper,we designed and synthesized a class of porphyrin-terminated amphiphilic hPEA,and studied their self-assembly behavior under different solvent systems.In addition,the PEA sponge was prepared by the ice template method.We introduced the functionalized molecules onto the PEA sponge and studied the selective adsorption characteristics of the obtained polymer sponge.The contents of each part are listed as follows:An ultralarge sheet with remarkable lateral dimensions of 10×10 μm–20×20 μm is fabricated by the hierarchical self-assembly of porphyrin-ended hyperbranched poly(ether amine)(tetraphenylporphyrin(TPP)–hPEA)in solution.The obtained TPP–hPEA amphiphiles can selfassemble from ultrathin single-layered nanosheets with a thickness of 4 nm to ultralarge multilayered nanosheets with thicknesses from 30 to 70 nm.The lateral dimensions increase from 2×2 μm to 5×5 μm,and eventually to 10×10 μm.Insitu dynamic light scattering and UV–vis spectroscopy studies suggest a hierarchical growth self-assembly mechanism with a self-assembly process that relies on π-π stacking.This 2D self-assembly method provides a significant potential guide for the preparation of ultralarge nanosheets in solution.Then,adjustment of the backbone structure of hPEA and the structure of the porphyrin molecule can well adjust the thickness,aspect ratio and morphology regularity of the ultralarge sheet.By changing the assembly solvent system,the self-assembly behavior of this type of polymer changes significantly from ultralarge sheet to hollow spherical structure.Then,we used the ice template method to prepare a functionalized poly(ether amine)sponge,which can achieve selective separation and adsorption of dyes and heavy metal ions.The functionalized sponge is a skeleton of a sponge formed by cross-linking of hyperbranched polyethyleneimine and polyethylene glycol glycidyl ether at a low temperature,and the presence of ice crystals provides a three-dimensional interconnected macroporous structure template for the sponge.Due to the existence of the ionic bond of the carboxyl group-amino group,caffeic acid is adsorbed to the surface of the pore wall of the sponge,followed by self-polymerization by oxidation catalysis,and a macrocyclic rigid structure of poly(caffeic acid)is formed on the surface of the sponge.We studied the adsorption characteristics of sponges for dyes with different structures by saturated adsorption experiments and dye adsorption kinetics systems,and established a dye adsorption model.At the same time,in sponge application,we carried out two aspects.One the one hand,the absorption-extrusion characteristics of the sponge are found to be able to quickly absorb industrial wastewater and then squeeze to achieve the efficacy of the dye during the adsorption period;On the other hand,the sponge is used as a filter element for filtering the dye in the wastewater.The above results indicate that the polyetheramine sponge prepared by the ice template method has great application prospects in wastewater treatment(dye separation and heavy metal adsorption).