Chung Kyeongwoon, McAllister Andrew, Bilby David, Kim Bong-Gi, Kwon Min Sang, Kioupakis Emmanouil, Kim Jinsang
Macromolecular Science and Engineering , University of Michigan , Ann Arbor , MI 48109 , USA . Email:
Department of Applied Physics , University of Michigan , Ann Arbor , MI 48109 , USA.
Chem Sci. 2015 Dec 1;6(12):6980-6985. doi: 10.1039/c5sc02403j. Epub 2015 Sep 3.
Building molecular-design insights for controlling both the intrachain and the interchain properties of conjugated polymers (CPs) is essential to determine their characteristics and to optimize their performance in applications. However, most CP designs have focused on the conjugated main chain to control the intrachain properties, while the design of side chains is usually used to render CPs soluble, even though the side chains critically affect the interchain packing. Here, we present a straightforward and effective design strategy for modifying the optical and electrochemical properties of diketopyrrolopyrrole-based CPs by controlling both the intrachain and interchain properties in a single system. The synthesized polymers, P1, P2 and P3, show almost identical optical absorption spectra in solution, manifesting essentially the same intrachain properties of the three CPs having restricted effective conjugation along the main chain. However, the absorption spectra of CP films are gradually tuned by controlling the interchain packing through the side-chain design. Based on the tailored optical properties, we demonstrate the encoding of latent optical information utilizing the CPs as security inks on a silica substrate, which reveals and conceals hidden information upon the reversible aggregation/deaggregation of CPs.
构建用于控制共轭聚合物（CPs）链内和链间性质的分子设计见解，对于确定其特性并优化其在应用中的性能至关重要。然而，大多数CP设计都集中在共轭主链上以控制链内性质，而侧链设计通常用于使CPs可溶，尽管侧链对链间堆积有至关重要的影响。在此，我们提出了一种直接有效的设计策略，通过在单一体系中同时控制链内和链间性质来改变基于二酮吡咯并吡咯的CPs的光学和电化学性质。合成的聚合物P1、P2和P3在溶液中显示出几乎相同的光学吸收光谱，表明具有沿主链受限有效共轭的这三种CPs的链内性质基本相同。然而，通过侧链设计控制链间堆积，可以逐渐调节CP薄膜的吸收光谱。基于定制的光学性质，我们展示了利用CPs作为二氧化硅基底上的安全墨水对潜在光学信息进行编码，这在CPs可逆聚集/解聚时可揭示和隐藏隐藏信息。
