Preparation and Charecterization of Charged Hollow Double-layer Polyelectrolyte Microspheres

Wang, D (Wang, Dan)^[ 1 ] ; Luo, LJ (Luo, Li-jie)^[ 2 ] ; Wu, GL (Wu, Gao-long)^[ 2 ] ; Liu, B (Liu, Bin)^[ 1 ] ; Chen, YJ (Chen, Yong-jun)^[ 2 ] ; Yang, XL (Yang, Xin-lin)^[ 1 ]

ACTA POLYMERICA SINICA, 2018, 7: 900-908

DOI: 10.11777/j.issn1000-3304.2018.18028

 WOS:000446262600012

Abstract

Monodisperse tetra-layer hybrid microspheres, the types of SiO2/anionic polymer/SiO2/anionic polymer and SiO2/anionic polymer/SiO2/cationic polymer, were prepared by a four-step synthetic procedure. The hollow double-shelled electrolyte microspheres, with either anionic species (-41.43 similar to -54.65 mV) on both shells or zwitterionic structures on the inner and outer shells, were prepared via combination of distillation precipitation polymerization and sol-gel method for the preparation of the tetra-layer inorganic/polymer hybrid microspheres together with the subsequently selective removal of silica core and sandwiched layer. In such a process, the modified Stober sol-gel technique was utilized for synthesis of silica inner core and the sandwiched third layer for these tetra-layer inorganic/polymer hybrid microspheres. The P(EGDMA-co-MAA) and P(DVB-co-St) polymeric layers were synthesized via the radical capture of EGDMA/MAA and DVB/St comonomers as well as their co-oligomers from the vinyl groups as the reactive sites with presence of the 3-(methacryloxy)propyl trimethoxysilane (MPS) silica nanoparticles as the seeds during the distillation precipitation polymerization. The outer P(DVB-co-StMPPy(+)Cl(-)) shell was further developed by a surface pyridinium reaction between the chloromethyl group on the surface of polymer network and the pyridine via suspension of SiO2/P(EGDMA-co-MAA)/SiO2/P(DVB-co-St) tetra-layer microspheres with various DVB crosslinking degrees (30 vol%, 50 vol% and 60 vol%) in pyridine. Transmission electron microscopy (TEM), Fourier transfer infrared spectra (FTIR) and zeta potential were systematically used for characterization of the morphology, chemical components and surface charges of these hollow double-layer polyelectrolyte microspheres. The resultant multi-layer inorganic silica/polymer multi-layer hybrid microspheres had smooth surface with regular shape with efficient interaction between the polymer layer and the inorganic species. The shape of the polymeric shells were deformed in the hollow polyelectrolyte microspheres due to shrinkage and collapse of the shells when they were slightly crosslinked. The thicknesses (12 - 59 nm) and zeta-potentials (8.82 - 39.82 mV) of the polymeric shell-layer can be facilely adjusted by changing the amount of DVB crosslinker in the comonomers (0.30 - 0.60) in the synthesis. The hollow double polymer electrolyte microspheres have great potential for applications as the active components in the field of methanol fuel cell for water reservoirs with high proton conductivity due to its huge cavities and zwitter-ionic channels for electron conductivity.