polymer compositesolid synthesis1

1 Solid State Synthesis • Solid State Reactions • Film deposition • Sol-gel method • Crystal Growth 2 • Synthesis References • The material we discussed in class was drawn primarily from the following sources: • A.R. West "Solid State Chemistry and its Applications" Chapter 2 – Preparative Methods • "Solid-State Chemistry – Techniques" Chapter 1 – Synthesis of Solid-State Materials J.D. Corbett – book edited by A.K. Cheetham and P. Day More detailed treatment, including practical details such as what sort of containers to use, how to avoid introducing impurities, what reactants to choose, etc., than above references. Corbett’s treatment is less oriented toward oxides, and more focussed on materials such as chalcogenides, halides and metal rich compounds. No discussion of thin films or growth of large crystals. • "Preparation of Thin Films" Joy George This book has a nice succinct treatment of the various thin film deposition methods. • The following references discuss various aspects or methods in solid state synthesis in greater detail. I have listed them according to synthesis method. • Low Temperature & Precursor Techniques • "Crystallization of Solid State Materials via Decomplexation of Soluble Complexes" K.M. Doxsee, Chem. Mater. 10, 2610-2618 (1998). "Accelerating the kinetics of low-temperature inorganic syntheses" R.RoyJ. Solid State Chem. 111, 11-17 (1994). "Nonhydrolytic sol-gel routes to oxides" A. Vioux, Chem. Mater. 9, 2292-2299 (1997). • 3 • Molten Salt Fluxes & Hydrothermal Synthesis • "Turning down the heat: Design and mechanism in solid state synthesis" A. Stein, S. W. Keller, T.E. Mallouk, Science 259, 1558-1563 (1993). • "Synthesis and characterization of a series of quaternary chalcogenides BaLnMQ3 (Ln = rare earth, M = coinage metal, Q = Se or Te)" Y.T. Yang, J.A. Ibers, J. Solid State Chem. 147, 366-371 (1999). • "Hydrothermal Synthesis of Transition metal oxides under mild conditions" M.S. Whittingham, Current opinion in Solid State & Materials Science 1, 227-232 • Chimie Douce & Low Temperature Synthesis "Chimie Douce Approaches to the Synthesis of Metastable Oxide Materials" J. Gopalakrishnan, Chem. Mater. 7, 1265-1275 (1995). • • High Pressure Synthesis "High pressure synthesis of solids" P.F. McMillan, Current Opinion in Solid State & Materials Science 4, 171-178 (1999) "High-Pressure Synthesis of Homologous Series of High Cricitcal Temperature (Tc) Superconductors" E. Takayama-Muromachi, Chem. Mater. 10, 2686-2698 (1998). "Preparative Methods in Solid State Chemistry" J.B. Goodenough, J.A. Kafalas, J.M. Longo, (edited by P. Hagenmuller) Academic Press, New York (1972). 4 Classification of Solids There are several forms solid state materials can adapt Single Crystal Preferred for characterization of structure and properties. Polycrystalline Powder (Highly crystalline) Used for characterization when single crystal cannot be easily obtained, preferred for industrial production and certain applications. Polycrystalline Powder (Large Surface Area) Desirable for further reactivity and certain applications such as catalysis and electrode materials Amorphous (Glass) No long range translational order. Thin Film Widespread use in microelectronics, telecommunications, optical applications, coatings, etc. 5 (1) Area of contact between reacting solids - We want to use starting reagents with large surface area to maximize the contact between reactants Consider the numbers for a 1 cm 3 volume of a reactant • Edge Length = 1 cm # of Crystallites = 1 Surface Area = 6 cm 2 • Edge Length = 10 μm # of Crystallites = 10 9 Surface Area = 6 x 10 3 cm 2 • Edge Length = 100Å # of Crystallites = 10 18 Surface Area = 6 x 10 6 cm 2 - Pelletize to encourage intimate contact between crystallites. Solid State Reactions 6 Time (h) 7 Different parts of the crystal have different structure and different reactivities 8 (2) The rate of diffusion Two ways to increase the rate of diffusion are to • Increase temperature • Introduce defects by starting with reagents that decompose prior to or during reaction, such as carbonates or nitrates. 9 10 (3) The rate of nucleation of the product phase • We can maximize the rate of nucleation by using reactants with crystal structures similar to that of the product (topotactic and epitactic reactions). a topotactic transformation is characterized by internal atomic displacements, which may include loss or gain of material so that the initial and final lattices are in coherence. epitaxy - The growth of the crystals of one mineral on the crystal face of another mineral, such that the crystalline substrates of both minerals have the same structural orientation.