Synthesis and physical characterization of arborescent (dendrigraft) polymers

我们的研究工作重点是具有树枝状结构的接枝聚合物，即树状聚合物（AP）的合成和物理表征。这些大分子具有2-100 nm的均匀尺寸、非常高的分子量（1E4-1E8）和支化官能度（f=10-10000）以及可控的化学组成。从基本角度来看，对这些材料结构的广泛控制对于在支化聚合物中建立结构-性能相关性及其在纳米技术相关应用中的利用非常有益。目前的提案确定了五个不同的活动领域：1）将检查具有聚电解质侧链的AP的溶液性质，特别关注中低极性溶剂中凝胶的形成，因为这些材料可用作pH敏感的智能凝胶。 2) 将研究两亲性 AP 在空气-水界面或溶液中的自组装能力，以产生上层结构（例如棒状和大型复合胶束组件）并在压力计刻度上形成表面图案。还将研究这些共聚物在水性环境中的疏水性化合物的溶解和释放，以作为疏水性药物的受控递送的模型系统。 3) 生物相容性增强的新型AP，可能用作实用的药物输送装置，将由氨基酸合成，并研究其溶解特性。 4) 将检查包含弹性链段的 AP 的流变性能，以加深对支化对聚合物加工性能影响的理解。 5）将开发一种使用“点击”化学的新接枝技术，以高产率合成具有长侧链的AP，这是迄今为止难以实现的。从拟议工作中获得的基础知识将有助于阐明支化对不同物理性质的影响，其支化功能范围比迄今为止使用星形支化聚合物等其他模型系统所实现的支化功能范围要广得多。

Our research efforts focus on the synthesis and the physical characterization of graft polymers with a dendritic architecture, the arborescent polymers (AP). These macromolecules have a uniform size ranging from 2-100 nm, very high molecular weights (1E4-1E8) and branching functionalities (f=10-10000+), and a controllable chemical composition. The extensive control achieved over the structure of these materials is highly beneficial, from a fundamental viewpoint, for the establishment of structure-property correlations in branched polymers, and for their utilization in nanotechnology-related applications. Five distinct activity areas have been identified in the current proposal: 1) The solution properties of AP with polyelectrolyte side chains will be examined, focusing particularly on the formation of gels in intermediate- to low-polarity solvents, as these materials may be useful as pH-sensitive smart gels. 2) Amphiphilic AP will be studied with respect to their ability to self-assemble, either at the air-water interface or in solution, to yield superstructures (e.g. rod-like and large compound micelle assemblies) and to pattern surfaces on the manometer scale. These copolymers will also be investigated for the solubilization and release of hydrophobic compounds in aqueous environments, to serve as model systems for the controlled delivery of hydrophobic drugs. 3) New AP with enhanced biocompatibility, potentially useful as practical drug delivery devices, will be synthesized from amino acids and investigated for their solubilization properties. 4) The rheological properties of AP incorporating elastomeric chain segments will be examined to improve the understanding of the influence of branching on polymer processability. 5) A new grafting technique using "click" chemistry will be developed to allow the high yield synthesis of AP with long side chains, which have been elusive so far. The fundamental knowledge gained from the proposed work will help clarify the influence of branching on different physical properties, over a much wider range of branching functionalities than has been achieved so far using other model systems such as the star-branched polymers.