How organic and inorganic hybrid increase thermalmechanical and electrical propertiescompounds differ?
Answers
Explanation:
Hybrid materials in nature In most cases the inorganic part provides mechanical strength and an overall structure to the natural objects while the organic part delivers bonding between the inorganic building blocks and/or the soft tissue. Typical examples of such materials are bone, or nacre.
Answer:
Homogeneously dispersed organic–inorganic hybrid nanocomposites can be obtained by increasing the interfacial interactions between both components via the formation of hydrogen bonds or covalent bonds, by mixing various polymers or via the adequate choice of the inorganic precursors. The mechanical response of these advanced functional materials is an issue of paramount importance when industrial applications are targeted. Large progress in the understanding of the mechanical properties of O–I hybrids has been gained by testing these materials under different conditions (static and dynamic, low and large deformations up to fracture) and using specific techniques developed for the mechanical characterization of conventional materials such as polymers, glasses or ceramics. However, the mechanical properties of hybrid O–I materials are dependent on their micro- and nanostructures and on the nature and extent of the O–I interfaces. Consequently, predictable mechanical properties for hybrids still represent a major challenge for hybrid materials science. Industrial attraction for hybrid materials has been emphasized by the development of new functional coatings. An important issue is the interface between the film and the substrate since strong adhesion can be tailored and ensures that delamination of the film will be limited.
Graphical abstract: Mechanical properties of hybrid organic–inorganic materials
Organic-inorganic hybrid materials are attracting a great deal of attention at the moment because they possibly possess the advantageous characteristics of both organic and inorganic materials [1]. The sol-gel method is one of the most promising techniques for producing organic-inorganic hybrids. It is a low-temperature solution process for preparing ceramics [2-4], and thus decomposition of the organic component can be minimized. However, most of the organic-inorganic hybrid materials prepared via the sol-gel method, e.g., ORMOSILs [5] are ceramics simply modified with an organic polymer or other functional groups and are not materials controlled on a meso-, or nano-scopic scale. Our major efforts have been devoted to the creation of a novel class of hybrid materials, which have a highly organized structure. Recently, we have prepared a novel class of hybrid materials, “Cerasome,” which form lipid-bilayer vesicles with a silicate framework on the surface from amphiphiles bearing a triethoxysilyl head and a dialkyl tail (Fig. 1) [6]. The key point of the formation process of the Cerasome is the hydrolysis behavior of the triethoxysilyl moiety. In the present study, we have synthesized two types of amphiphiles with a triethoxysilyl head. We investigated the effect of the structure of the hydrophilic group on the hydrolysis process to optimize the catalytic conditions for the preparation process of Cerasome.
Hybrid inorganic–organic materials are a promising system for a variety of applications due to their properties based on the combination of different building blocks. The ideal procedure for the generation of hybrid inorganic–organic materials is the sol–gel process that involves a molecular precursor as a starting material, followed by the formation of oxide frameworks by hydrolysis and condensation reaction [219]. The sol–gel process is particularly attractive because it presents advantages such as high purity of reactants and final products, mild processing conditions, and it is possible to control connectivity and morphology by suitable choice of reactants, catalyst, and reaction conditions. Additionally, it is transparent due to the nanosized organic and inorganic domains, easy to apply on any kind of substrates, and easy inclusion of suitable organic or inorganic of active substances for the preparation of functional hybrid materials [220].
Corradini et al. [222] dip-coated cold plasma–treated PET films vertically at a constant speed of 7.0 cm/min into a sol–gel-containing lysozyme. These films showed inhibition of Micrococcus lysodeikticus on agar plates at concentrations of 1.25 mg/mL indicating significant potential for the use of these packaging materials as a food preservative. Lantano et al. [223] developed PLA films activated using a sol–gel process, employing tetraethoxysilane as a precursor of the inorganic phase and polyvinyl alcohol as the organic component, and incorporating natamycin as the active agent. Activated PLA films were applied on cheese where after 30 days storage at 4°C, no mold growth was observed on the cheese surface, compared with extensive mold growth on inactivated PLA films