MACROSCOPIC SELF-ASSEMBLY OF ORGANOGELS THROUGH QUADRUPLE HYDROGEN BONDING

A methyl acrylate monomer MAMIS with ureidopyrimidinone (UPy) unit was synthesized. The molecular structure of MAMIS was confirmed by H-1 nuclear magnetic resonance (H-1-NMR) spectrum, Fourier-transform infrared (FTIR) spectrum, electrospray ionization-mass (ESI-MS) spectrum and elemental analysis. A kind of organogel with UPy units (defined as UPy-gel) was prepared through traditional radical copolymerization of MAMIS and other acrylate monomers in DMSO. The chemical composition and morphology of the UPy-gel were characterized by elemental analysis, FT-IR, and scanning electron microscopy (SEM). The glass transition temperature (T-g) of the gels was measured by using a differential scanning calorimeter (DSC). Compared with the oganogels without UPy units,the UPy-gel displays similar microscopic morphology and an increased T-g. The macroscopic assembly of the gels under the driving of UPy quadruple hydrogen bonding was further investigated. The results indicated that the UPy-gel pieces aggregated together in toluene, and the aggregated UPy-gels gradually separated in DMSO. This process could be repeated for many times. As increasing the content of UPy units in the gels or by using a solvent with lower polarity, the aggregation strength of the gels became higher, demonstrating the solvent-sensitivity of the gels. Driven by quadruple hydrogen bonding, the macroscopic assembly of the gels enabled the transmission of dye molecules from dyed gels to undyed ones.