Supramolecular assembly of H-bonded copolymers/complexes/nanocomposites and fluorescence quenching effects of surface-modified gold nanoparticles on fluorescent copolymers containing pyridyl H-acceptors and acid H-donors
作者:Tzung-Chi Liang、Hong-Cheu Lin
DOI:10.1039/b823450g
日期:——
A series of photoluminescent (PL) and liquid crystalline (LC) self-H-bonded side-chain copolymers (P1–P3) consisting of pyridyl H-acceptors and isomeric acid H-donors (i.e., para-, meta-, and ortho-benzoic acids) were synthesized. Supramolecular H-bonded complexes were also obtained by mixing the photoluminescent H-acceptor homopolymer PBT1 (containing pyridyl pendants) with isomeric H-donor homopolymers P7–P9. The formation of H-bonds was confirmed by FTIR, DSC, and XRD measurements. Moreover, PL and LC properties of the H-bonded copolymers and complexes were affected not only by the H-bonding effect of the supramolecular structures but also by the acid-substituted positions of isomeric H-donors. In combination with different functionalized gold nanoparticles (which bear acid or acid-free surfactants), the emission intensities of nanocomposites containing self-H-bonded copolymer P1 (bearing both H-acceptor and H-donor moieties) and non-self-H-bonded copolymer P4 (bearing acid-protected moieties), were quenched to different extents by varying the concentration of gold nanoparticles. The copolymeric H-acceptors and surface-modified gold nanoparticles demonstrated diverse morphological and PL quenching effects on the supramolecular architectures of the nanocomposites, which result from competition between the H-donors from the acid pendants on copolymers and the acid surfactants on the gold nanoparticles.
一系列光致发光(PL)和液晶(LC)自氢键侧链共聚物(P1-P3),由吡啶基氢受体和异构酸氢供体(即对位、间位和邻位苯甲酸)组成,已被合成。通过混合光致发光氢受体均聚物PBT1(含吡啶侧链)与异构氢供体均聚物P7-P9,也获得了超分子氢键复合物。氢键的形成通过FTIR、DSC和XRD测量得到证实。此外,氢键共聚物和复合物的PL和LC性质不仅受到超分子结构氢键效应的影响,还受到异构氢供体酸取代位置的影响。结合不同功能化的金纳米颗粒(带有酸或无酸表面活性剂),包含自氢键共聚物P1(带有氢受体和氢供体基团)和非自氢键共聚物P4(带有酸保护基团)的纳米复合材料的发光强度,通过改变金纳米颗粒的浓度而被不同程度地淬灭。共聚物氢受体和表面修饰的金纳米颗粒对纳米复合材料的超分子结构表现出不同的形态和PL淬灭效应,这是由于共聚物上的酸侧链的氢供体和金纳米颗粒上的酸表面活性剂之间的竞争所致。