合成了一种带有脲基嘧啶酮(ureidopyrimidinone,UPy)四重氢键单元的甲基丙烯酸酯类单体MAMIS,并用氢核磁(^1H-NMR)、红外光谱(FTIR)、电喷雾质谱(ESI—MS)和元素分析确认其结构.以二甲基亚砜(DMSO)为溶剂,基于MAMIS及丙烯酸酯类单体的自由基共聚,合成了一种带有UPy单元的有机凝胶,采用元素分析、红外光谱和扫描电子显微镜(SEM)表征了凝胶的组成及形貌,并采用差示扫描量热仪(DSC)测定了干凝胶的玻璃化转变温度(Tg).与不含UPy单元的凝胶相比,UPy单元的引入显著提高了干凝胶的r。,但基本不影响凝胶的微观形貌.研究了UPy凝胶在UPy四重氢键驱动下的宏观自组装行为,结果表明UPy凝胶块在甲苯中聚集,在DMSO中分离,该过程可多次重复.随着UPy单元含量的增加及溶剂极性的降低,凝胶块的结合强度逐渐增加,体现出溶剂敏感性.基于四重氢键驱动的宏观自组装,可以实现染料分子在不同凝胶块间的传递.
A methyl acrylate monomer MAMIS with ureidopyrimidinone (UPy) unit was synthesized. The molecular structure of MAMIS was confirmed by 1 H nuclear magnetic resonance ( 1 H-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 (Tg) 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 Ts. 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.