摘要
合成了两亲性的聚(γ-苄基-L-谷氨酸酯)-b-聚乙二醇(PBLG-b-PEG)聚肽刚-柔嵌段共聚物和聚苯乙烯(PS)均聚物及多种聚苯乙烯衍生物,包括聚(4-乙酰氧基苯乙烯)(PAS)均聚物、聚(4-羟基苯乙烯)(PVPh)均聚物和聚(苯乙烯-co-4-乙酰氧基苯乙烯)(P(S-co-AS))共聚物.用傅里叶变换红外光谱(FTIR)、核磁共振氢谱(1H-NMR)和凝胶渗透色谱(GPC)等表征了聚合物的结构、分子量及分布.采用共溶剂溶解、选择性溶剂透析的方法,制备了PBLG-b-PEG嵌段共聚物与不同PS衍生物(包括PS均聚物)共混体系的自组装聚集体,利用透射电子显微镜(TEM)和扫描电子显微镜(SEM)等表征了自组装体的形貌和结构.研究发现,不同的分子间相互作用(如π-π共轭作用、偶极-偶极相互作用、氢键作用等)对共混体系的自组装形貌有显著的影响.PBLG-b-PEG/PS共混体系自组装可形成表面具有条纹结构的"毛线球"聚集体,该体系中PBLG和PS之间形成π-π共轭作用,相互作用强度相对较弱;PBLG-b-PEG/PAS共混体系自组装可形成表面基本光滑并有轻微凹陷的球形聚集体,该体系中PBLG和PAS之间除了π-π共轭作用,还可形成相对较强的偶极-偶极相互作用;而PBLG-b-PEG/PVPh共混体系自组装得到了囊泡,该体系中PBLG与PVPh之间可形成π-π共轭和氢键作用,相互作用强度进一步增强.对于PBLG-b-PEG/P(S-co-AS)共混体系,可通过改变P(S-co-AS)共聚物中AS摩尔分数和制备温度来调控自组装聚集体表面的条纹形貌.根据PBLG链段与不同PS衍生物(包括PS均聚物)之间不同的分子间相互作用,提出了上述聚集体形貌转变的机理.
Herein, poly（γ-benzyl-L-glutamate）-b-poly（ethylene glycol）（PBLG-b-PEG） polypeptide-based rod-coil bl℃k copolymer, polystyrene homopolymer（PS）, and PS derivatives, such as poly（4-acetoxystyrene）（PAS） homopolymer, poly（vinylphenol）（PVPh） homopolymer, and poly（styrene-co-4-acetoxystyrene）（P（S-coAS）） copolymer with various AS molar contents, were synthesized. The molecular structures（molecular weight, polydispersity index and composition） of the polymers were characterized by Fourier transform infrared spectroscopy（FTIR）, nuclear magnetic resonance spectroscopy（1 H-NMR） and gel permeation chromatography（GPC）. Self-assembly behaviors of the polymer blends composed of PBLG-b-PEG copolymer and PS derivatives（including PS homopolymer） were explored. The self-assembled aggregates were prepared by a dialysis method with water used as selective solvent. The morphologies and structures of the formed aggregates were investigated by transmission electron microscopy（TEM） and scanning electron microscopy（SEM）. The influence of intermolecular interaction between polymers（e.g., π-π interaction between PBLG and PS, PAS and PVPh, dipole-dipole interaction between PBLG and PAS, and hydrogen-bonding interaction between PBLG and PVPh） on self-assembly behaviors of the polymer blends was investigated. With the strength of intermolecular interaction increasing in the order of PBLG/PS PBLG/PAS PBLG/PVPh, a morphological transition was observed. With relatively weak intermolecular interaction, strip-pattern-spheres were formed in the PBLG-b-PEG/PS blends. For PBLG-b-PEG/PAS blends, as the dipole-dipole interaction was stronger than π-π interaction, the strips disappeared and cavity was observed. As the intermolecular interaction was further enhanced by hydrogen bonding, vesicles were self-assembled in PBLG-b-PEG/PVPh blends. Additionally, the surface morphology of the spherical aggregates was tuned by AS molar content and temperature for PBLG-b-PEG/P（S-co-AS） blends. With increasing AS molar content, the dipole-dipole interaction between PBLG and P（S-co-AS） increased, leading to less regular strip patterns on aggregates surfaces compared with PBLG-b-PEG/PS polymer blends. As temperature increases, the strip patterns became more regular due to the weaker interaction between PBLG and PSAS segments.
出处
《高分子学报》
SCIE
CAS
CSCD
北大核心
2018年第1期109-118,共10页
Acta Polymerica Sinica
基金
国家自然科学基金(基金号51573049
21234002
21474029)资助项目
关键词
自组装
共混
分子间相互作用
聚肽
形貌转变
Self-assembly, Blends, Intermolecular interaction, Polypeptides, Morphological transition
