Syntheses of complex mesoporous silicas using mixtures of nonionic block copolymer surfactants: understanding formation of different structures using solubility parameters.
نویسندگان
چکیده
The use of block copolymer (BCP) nonionic surfactant mixtures (including Pluronic, Brij and Tetronic types) as templates for synthesizing porous silica materials of mixed pore sizes is explored here. These systems have important applications because combinations of pore sizes can allow rapid access of reactants (via large pores) whilst providing the very high surface area of small pores for higher reaction rates or size selectivity. Examples of the materials prepared here include pore size bimodal hexagonal p6mm channel structures and cubic Im3m cage structures. It is shown here that the chemical similarity, as indicated by the solubility parameter, of the surfactants is an important factor in determining the pore structure and size distribution (PSD) of the pores. Monomodal pore structures are usually obtained when the solubility parameters of the surfactants are similar and bimodal pore structures when the solubility parameters are reasonably different. When the interaction parameter is very high disordered porous systems are formed. Ternary co-surfactant systems, e.g. P123-25R4-P65, can also yield highly ordered bimodal mesoporous silica with a hexagonal structure.
منابع مشابه
Ordered Nanoporous Carbon Structures Synthesized Using Large-pore Mesoporous Silica Templates
Poly(alkylene oxide)-type block copolymers have been recently shown to be particularly versatile as structure-directing agents for the preparation of ordered large-pore mesoporous silica materials. In principle, the structure direction is achieved through the formation of periodic supramolecular self-assemblies between the polymeric surfactants and a silica source in the aqueous solution. The o...
متن کاملSynthesis of Mesoporous Silica Materials by Using Anionic Surfactants as Template
1. 1. Well-ordered Mesoporous Materials FSM-16 and M41S materials with regularly ordered mesopore arrangements and narrow pore-size distributions were fi rst described in the early 1990s1),2), and the mesostructures of silica and various metal oxides have since attracted much attention from chemists and materials scientists because of emerging applications in catalysis, adsorption, sensors, and...
متن کاملEvaluation of the Effect of Nonionic Surfactants and TBAC on Surface Tension of CO2 Gas Hydrate
Given that most of the gaseous constituents of industrial chimneys are usually carbon dioxide which is one of the most important greenhouse gases. It seems that the hydration process is one of the newest methods for the separation of this gas from gaseous mixtures. In the gas hydrate formation industry, in addition to disadvantages, there are some advantages such as gas separation, transmission...
متن کاملStudy of mixed micelles and interaction parameters for polymeric nonionic and normal surfactants.
Surface tension (ST) measurements were carried out on various binary mixtures of the "normal" surfactants, such as nonionic surfactant, hexaethylene glycol mono-n-dodecyl ether(C12EO6), and cationic surfactant, tetradecyltrimethylammonium bromide (TTAB), and polymeric copolymer, Pluronic F127, F127(PPO)-g-PVP, and F127(PEO)-g-PVP. In all cases mixed micellar aggregates were formed and critical ...
متن کاملMultiphase Assembly of Mesoporous-Macroporous Membranes
The synthesis of inorganic-organic composites and mesoporous materials with structures and functions over different length scales has ramifications in diverse areas, such as large-molecule catalysis, biomolecule separations, miniaturization of electronic devices, chromatographic supports, the formation of semiconductor nanostructures, and the development of medical implants.1-8 The use of organ...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Journal of colloid and interface science
دوره 353 1 شماره
صفحات -
تاریخ انتشار 2011