Abstract

Novel bridged silsesquioxanes (BSs) incorporating short oligo(oxypropylene) or oligo(oxyethylene) chains bonded to a siliceous network via urea cross-links were synthesized by the sol–gel process from the organosilane precursors (CH₃CH₂O)₃-Si-(CH₂)₃-NHC(=O)NH-R-NH(O=C)NH-(CH₂)₃-Si-(OCH₂CH₃)₃, with R≡-[CH(CH₃)CH₂O]_xCH₂CH(CH₃)- (x∼2.5 and 6.1) or R≡-(CH₂)₂O(CH₂)₂O(CH₂)₂-, respectively. The new BSs were identified by the notations d-U′(Y′) with Y′ = 400 and 230, and d-U(Y) with Y = 148, where d stands for di, and U/U′ denote the urea group. The hybrid materials were produced as transparent, amorphous, homogeneous, and soft monoliths, although d-U(148) presented some rigidity. In the three samples the siliceous framework is mainly composed of [–(CH₂)Si(OSi)₃] and [–(CH₂)Si(OSi)₂(OH)] substructures. The highest polycondensation degree of the siloxane network was found in the case of d-U′(400), pointing out the formation of a three dimensional framework. In the three materials the urea groups are extensively involved in the formation of strong ordered urea-urea hydrogen-bonded aggregates of different degree of order. The d-U′(230) BS is a promising candidate as mold material for micropatterning applications aiming the fabrication of smart coatings. The prospects for these materials in flexible electrochromic devices for smart windows, where they can act as outermost substrates, are also excellent.

中文翻译：

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掺有低聚（氧丙烯）和低聚（氧乙烯）链的双脲交联硅氧烷杂化材料

摘要

通过溶胶-凝胶法由有机硅烷前体（CH ₃ CH ₂ O）₃ -Si合成了新型桥联倍半硅氧烷（BSs），其通过尿素交联键合到硅质网络上，形成了短的低聚（氧化丙烯）或低聚（氧化乙烯）链-（CH ₂）₃ -NHC（= O）NH-R-NH（O = C）NH-（CH ₂）₃ -Si-（OCH ₂ CH ₃）₃，其中R 1-[CH（CH ₃） CH ₂ O] _x CH ₂ CH（CH ₃）-（x〜2.5和6.1）或R 1-（CH ₂）₂ O（CH ₂）₂分别为O（CH ₂）_2-。新的BS用符号dU'（Y '）（Y '= 400和230）和dU（Y）（Y  = 148 ）标识，其中d代表di，U / U'代表脲基。尽管dU（148）具有一定的刚度，但杂化材料还是透明，无定形，均质和柔软的整体材料。在这三个样品中，硅质骨架主要由[–（CH ₂）Si（OSi）₃ ]和[–（CH ₂）Si（OSi）_2组成。（OH）]子结构。在dU'（400）的情况下，发现硅氧烷网络的最高缩聚度，指出了三维骨架的形成。在这三种材料中，尿素基团广泛参与不同顺序程度的强有序尿素-尿素氢键结合聚集体的形成。dU'（230）BS是用于微图案化应用的模具材料的有前途的候选者，旨在用于智能涂层的制造。这些材料可用于智能窗户的柔性电致变色设备中，它们可以用作最外层的基材，其前景也非常好。