Thermal Behavior of Caged Silsesquioxane (POSS) Studied by Molecular Dynamics Simulations

Abstract

In order to simulate the thermal behavior of one of the most useful inorganic-organic hybrid materials, octa-functional polyhedral oligomeric silsesquioxane (POSS), molecular dynamics (MD) simulations of crystals of POSSs having methyl, i-butyl, and cyclopentyl substituents were performed using the universal force field. The crystal structures obtained by the MD calculations were in good agreement with those reported based on experimental results. On the basis of their molecular expansion behaviors, the lattice lengths were also evaluated, from which the expansion of each lattice length as a function of temperature was found to be dependent upon the substituents.

Unsymmetric Dumbbell-Shaped Polyhedral Oligomeric Silsesquioxane (POSS) Compound as a Single-Component POSS Hybrid

“…Thus, they are regarded as organic–inorganic hybrid molecules in which the organic substitutes act as molecular-level-softened segments and the inner T 8 -caged framework provides improved mechanical and thermal properties to suppress their movements. Crystallinity and thermal behavior of the POSS derivatives are highly dependent on their organic substituents, − which are alkyl substituents such as methyl, isobutyl, cyclopentyl, and fluoroalkyl groups and aryl substituents such as the phenyl group. The melting points and nonmelting behavior prior to the decomposition of the POSS derivatives are very much dependent on their substituents .…”

“…Crystallinity and thermal behavior of the POSS derivatives are highly dependent on their organic substituents, − which are alkyl substituents such as methyl, isobutyl, cyclopentyl, and fluoroalkyl groups and aryl substituents such as the phenyl group. The melting points and nonmelting behavior prior to the decomposition of the POSS derivatives are very much dependent on their substituents . Completely different thermal behavior between alkyl- and phenyl-substituted POSSs due to the intrinsic stability of organic groups results in higher thermal stability for the latter compounds …”

“…The melting points and nonmelting behavior prior to the decomposition of the POSS derivatives are very much dependent on their substituents. 17 Completely different thermal behavior between alkyl-and phenylsubstituted POSSs due to the intrinsic stability of organic groups results in higher thermal stability for the latter compounds. 18 Solubility and compatibility of the POSS compounds are also dependent on their substituents.…”

Synthesis and Thermal Behaviour of Novel Aliphatic/Aromatic Hepta-Cyclopentyl Bridged Polyhedral Oligomeric Silsesquioxanes (POSSs)/Polystyrene (PS) Nanocomposites

“…These substances can be considered the achievement of the chemists dream of unifying in the same products the different characteristics of both inorganic and organic compounds, different from those we can obtain by a simple blend at macroscopic level. POSSs have considerable importance owing to their excellent thermal, mechanical, optical and electrical properties [2][3][4][5][6] due to both their nanosized and cubic structure and inorganic cage [7], which allow their employment in several fields: as, for example, sensors [8], electrolyte for ion exchange membrane in fuel cell applications [9,10], novel curing agent and/or filler for epoxy system [11,12]. In the last years POSSs acquired further increasing importance due to their employment as fillers for polymer based nanocomposites [13,14] and new methods for combination of POSS and polymers has been proposed [15].…”

Cross‐linking SixOy Cages with Carbon by Thermally Annealing Polyhedral Oligomeric Silsesquioxane: Structures, Morphology, and Electrochemical Properties as Lithium‐Ion Battery Anodes

“…[11] The thermal stabilitya nd degradation of POSS has been widelyi nvestigated by many research groups. [12] In the presence of air,h igh-temperature treatmentn ormally converts POSS to silica. However,t he thermalb ehavioro fP OSS in an inert environmenti sm ore complicated and mayv ary significantly from complete decomposition to partial retention of the cage structure, depending on the nature of the attached organic groups.…”