Synthesis of an Open‐Cage Structure POSS Containing Various Functional Groups and Their Effect on the Formation and Properties of Langmuir Monolayers

Abstract

Recently, silsesquioxanes have been recognized as a new group of film-forming materials. This study has been aimed at determining the effect of the kind of functional groups present in two different open-cage structure POSS molecules on the possibility of the formation of Langmuir monolayers and their properties. To achieve this goal, two new POSS derivatives (of open-cage structures) containing polyether and fluoroalkyl functional groups have been synthesized on the basis of a hydrosilylation process. An optimization of the process was performed, which makes it possible to obtain the above-mentioned derivatives with high yields. In the next step, the Langmuir technique was applied to measurements of the surface pressure (π) - the mean molecular area (A) isotherms during the compression of monolayers formed by molecules of the two POSS derivatives considered. Subsequently, the monolayers were transferred onto quartz plates according to the Langmuir-Blodgett technique. Both derivatives are able to form insoluble Langmuir films at the air-water interface, which can be transferred onto a solid substrate and effectively change its wetting properties.

Organic–inorganic polyurethanes with double decker silsesquioxanes in the main chains: Morphologies, surface hydrophobicity, and shape memory properties

“…In a typical POSS molecule, SiOSi linkages constitute a cage‐like and polyhedral framework; at each vertex of the polyhedron, each Si atom is covalently bonded to an organic R group. The well‐defined nanostructures inspire investigators to incorporate POSS molecules to afford the organic–inorganic nanocomposites with improved thermomechanical and even new functional properties . To facilitate introducing the organic–inorganic cages into organic polymers, POSS molecules would be functionalized with one (or more) reactive R group.…”

Preparation of Tri(alkenyl)functional Open-Cage Silsesquioxanes as Specific Polymer Modifiers

“…They are soluble in organic solvents like DCM, CHCl 3 , THF, and toluene but not in, e.g., methanol, MeCN, and hexane (only for R = Ph). They were isolated and characterized by employing spectroscopic methods ( 1 H, 13 C, and 29 Si NMR, as well as FT-IR, see Supplementary Materials). All of these condensation reactions (Figure 1Error!…”

“…They are air-stable solids, waxy solids, or colorless oils, and can be synthesized on a In the case of -hex-3-enyl (FG =Hex) and -dec-5-enyl (FG = Dec) functionalities, a parallel synthetic methodology that was based on the hydrosilylation reaction was also verified. For this purpose, we prepared silsesquioxane derivatives with three Si-H reactive groups (SQ-R-SiH, R = iBu, Ph), via hydrolytic condensation of trisilanol SQ-iBu-OH (R = iBu, Ph) form with ClSiMe 2 H basing on the procedure known from the literature [13] (see paragraph 2.3). The resulting SQ-R-SiH (R = iBu, Ph) were reagents for tests of hydrosilylation reaction with 1,5-hexadiene and 1,9-decadiene that was proceeded while using Karstedt's catalyst ( Figure 2).…”

“…On the other hand, open-cage silsesquioxanes, i.e., not-completely condensed systems have recently attracted much attention. The silsesquioxane trisilanol precursors enable the introduction of three reactive substituents to the Si-O-Si core by means of stoichiometric (hydrolytic condensation), but also catalytic (e.g., hydrosilylation, arylation, O-silylation), processes using functional groups that are already attached to the SQ core [8][9][10][11][12][13][14][15][16]. The symmetry of their trifunctional T 7 open-cage derivatives is changed due to the lack of one vertex in the structure, which affects their physical properties (i.e., changes in molecular packing, melting points) [9,[17][18][19][20].…”

“…However, they offer interesting synthetic possibilities due to the opportunity to introduce more than one functional group within the silsesquioxanes core bearing at the same time also inert ones. As a result, the perspectives for the further development of this group of compounds are vast, from nanostructured coating films [13], silica-grafted catalysts [21,22], tripodal ligands for transition metals [23], novel cage host molecules [24], aggregates in cosmetics and food manufacturing [25,26], or dentistry [27,28] to polymers modifiers as cross-linking agents [29][30][31][32][33][34]. Multi-functional SQs may additionally offer the possibility to obtain three-dimensional (3D) copolymeric networks, leading to substantial improvement in their physicochemical properties, i.e., increased thermal and oxidation resistance, mechanical properties, e.g., hardness, as well as the reduction of flammability, heat evolution, viscosity during processing, etc.…”