Ayzac Virgile, Sallembien Quentin, Raynal Matthieu, Isare Benjamin, Jestin Jacques, Bouteiller Laurent
Sorbonne Université, CNRS, Institut Parisien de Chimie Moléculaire, Equipe Chimie des Polymères, 75005, Paris, France.
Laboratoire Léon Brillouin, UMR 12 CNRS-CEA, 91191, Gif-sur-Yvette Cedex, France.
Angew Chem Int Ed Engl. 2019 Sep 23;58(39):13849-13853. doi: 10.1002/anie.201908954. Epub 2019 Aug 19.
Introduction of competing interactions in the design of a supramolecular polymer (SP) creates pathway complexity. Ester-bis-ureas contain both a strong bis-urea sticker that is responsible for the build-up of long rod-like objects by hydrogen bonding and ester groups that can interfere with this main pattern in a subtle way. Spectroscopic (FTIR and CD), calorimetric (DSC), and scattering (SANS) techniques show that such ester-bis-ureas self-assemble into three competing rod-like SPs. The previously unreported low-temperature SP is stabilized by hydrogen bonds between the interfering ester groups and the urea moieties. It also features a weak macroscopic alignment of the rods. The other structures form isotropic dispersions of rods stabilized by the more classical urea-urea hydrogen bonding pattern. The transition from the low-temperature structure to the next occurs reversibly by heating and is accompanied by an increase in viscosity, a rare feature for solutions in hydrocarbons.
在超分子聚合物（SP）设计中引入竞争性相互作用会产生路径复杂性。酯基双脲既含有一个强双脲黏附基团，该基团通过氢键作用负责形成长棒状物体，又含有酯基，酯基会以一种微妙的方式干扰这种主要模式。光谱（傅里叶变换红外光谱和圆二色光谱）、量热（差示扫描量热法）和散射（小角中子散射）技术表明，此类酯基双脲会自组装成三种相互竞争的棒状超分子聚合物。此前未报道的低温超分子聚合物通过干扰性酯基与脲部分之间的氢键得以稳定。它还具有棒状结构的弱宏观排列。其他结构则形成由更经典的脲 - 脲氢键模式稳定的棒状各向同性分散体。通过加热，从低温结构到下一种结构的转变是可逆的，并且伴随着粘度的增加，这对于烃类溶液来说是一个罕见的特征。
