Promising Functional Materials Based on Ladder Polysiloxanes

Abstract

Preparation of real ladder polysiloxanes (LPSs), including both oxygen‐bridged ladder polysilsesquioxanes (LPSQs) and organo‐bridged ladder polysiloxanes (OLPSs), had been a great challenge to polymer chemists from 1960 until the successful synthesis of LPSs via the supramolecular architecture‐directed stepwise coupling polymerization (SCP) in the early 1980s. This opened up a new field of LPS‐based advanced materials. As key building blocks, LPSs are used to construct a variety of polysiloxanes with special steric configurations and functions, such as mesomorphic LPSs, tubular polysiloxanes (TPs), and pseudo‐sieve‐plate polysiloxanes (pseudo‐SPSs). With excellent temperature and radiation resistance, good solubility, and fine optical and mechanical properties, all these polysiloxanes demonstrate very promising prospects in the advanced materials realm. Here, the synthesis of well‐ordered LPSs is presented and features of fishbone‐like and rowboat‐like liquid crystalline polysiloxanes are discussed. Special emphasis is given to typical applications of LPSs, TPSs, and pseudo‐SPSs in the areas of liquid crystal displays, microelectronics packaging, and nonlinear optical materials.

Carbazole-based polymers as hosts for solution-processed organic light-emitting diodes: Simplicity, efficacy

“…As justifications of this choice, polysiloxanes exhibit good solubility in most of the common organic solvents, good film-forming ability as well as an excellent resistance to chemical, photochemical and thermal degradation [154][155][156].…”

Alkali-Metal-Directed Hydrolytic Condensation of 3-Mercaptopropyltrimethoxysilane

“…The influence of the amount of potassium hydroxide on the structure of cyclotetrasiloxanolate-(CH 2 ) 3 29 Si CP MAS NMR analysis ( Fig. 1) displayed only one peak, at -60.4 ppm, for the potassium cyclosiloxanolate obtained with method 1 (Table 1/ entry 2).…”

“…Exhibiting many excellent properties, such as outstanding thermooxidative and photochemical stability, low flammability, excellent dielectric properties and mechanical stability, ladder-like polysilsesquioxanes can be applied as protective M. Nowacka ( ) · A. Kowalewska · K. Gadzinowska Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, Sienkiewicza 112, 90-363 Lodz, Poland e-mail: mnowacka@cbmm.lodz.pl coatings, insulating layers, aerospace materials and precursors of ceramics, photoresists etc. [1,3]. In addition, LPSQs (even those of high molecular weight) are well soluble in organic solvents.…”

“…Several synthetic methods were proposed for the preparation of ladder-like polysilsesquioxanes, including step wise coupling polymerization [3][4][5][6][7] or hydrolytic condensation of trifunctional organosilanes [2,[8][9][10]. However, the most promising method for the preparation of defect-free LPSQs is hydrolytic condensation of monomers containing cyclic siloxane units [11][12][13][14][15][16][17][18][19].…”

Synthesis of ladder-like polyphenylsilsesquioxanes with fairly high regularity using 1,2-ethylenediamine as endo-template

“…Later, a white solid was precipitated after the filtrate was mixed with an equal mass of n-hexane. [26] . …”