含MPEG侧链的膦手性螺旋聚合物自组装材料的合成与表征

SYNTHESIS AND SELF-ASSEMBLY OF P-CHIRALITY HELICAL POLYMERS CONTAINING MPEG SIDE CHAINS

合成了一种新型含薄荷醇基苯氧基丙炔膦酰胺单体(1a)和含不同长度MPEG侧链的丙炔酸酯单体(1b～3b).采用柱层析及诱导结晶拆分对映体(1a),31P-NMR表征可知对映体1a可成功拆分,以(nbd)Rh+[η6-C6H5B-(C6H5)3]为催化剂,对单体1a进行均聚,单体1a与1b～3b进行共聚,制得产率42.6%～80.3%,相对数均分子量Mn=1.8×104～2.4×104的聚合物.圆二色光谱(CD)紫外(UV-Vis)表征发现聚合物具有很强的光学活性且能形成单一方向的螺旋构象.探究发现随共聚物中b嵌段分子量增加其螺旋性能逐渐增强,研究发现不同配比的CH3Cl/CH3OH混合溶剂对均聚物及共聚物二级结构的影响差异显著.聚合物在不同溶剂中可以组装成球形以及棒状等形态.

Novel chiral N-propargylphosphonamidate monomers containing phenoxyl,imentholyl groups（1a） and propargyl esters having PEG side chain（1b-3b） with different lengths were synthesized by successive condensation.The single peak in the 31P-NMR spectrum indicated that pure diastereomer（1a） was obtained by using column chromatography on silica gel and then recrystallizing.The corresponding polymers with moderate molecular weights（Mn=1.8×104~2.5×104） in good yields（42.6%~80.3%） were synthesized by copolymerization of the diastereomer（1a） using（nbd）Rh＋[η6-C6H5B-（C6H5）3] as catalyst.The polarimetric,CD and UV-Vis spectroscopic data revealed that polymers existed in a helical form with one-handed screw sense predominantly in CHCl3 solvent.This study further shows that the helical structure was influenceed by internal and external factors.When the molecular weight of b block increases,the intensity of CD becomes higher.It was found that the secondary structure stability of the copolymer was better than homopolymer＇s in different mixed solvents.When the methanol quantity was up to 50%,the CD spectra changeed into positive and negative parts caused by the accumulation of the polymers.The assembly phenomenon of the Poly（1a-co-3b） was studied in different solvent systems（CHCl3/CH3OH,THF/H2O）.It is clear from the SEM images of these systems,Poly（1a-co-3b） can be assembled into spherical shape and rodlike micellae in different solvents.