Surfactant-Controlled Polymerization of Semiconductor Clusters to Quantum Dots through Competing Step-Growth and Living Chain-Growth Mechanisms

2012 ◽  
Vol 134 (41) ◽  
pp. 17298-17305 ◽  
Author(s):  
Christopher M. Evans ◽  
Alyssa M. Love ◽  
Emily A. Weiss
Keyword(s):  
Quantum Dots ◽  
Chain Growth ◽  
Growth Mechanisms ◽  
Controlled Polymerization ◽  
Semiconductor Clusters ◽  
Step Growth

Chain growth polymerization mechanism in polyurethane-forming reactions

RSC Advances ◽  
2015 ◽  
Vol 5 (84) ◽  
pp. 68361-68368 ◽  
Author(s):  
R. Ghoreishi ◽  
G. J. Suppes
Keyword(s):  
Chain Growth ◽  
Growth Mechanisms ◽  
New Approach ◽  
Polymerization Mechanism ◽  
Step Growth ◽  
Catalytic Mechanisms

A new approach simulates alcohol–isocyanate reactions in polyurethane systems: catalytic mechanisms dominate the kinetics and chain growth mechanisms overwhelm step growth.

Polymer Chemistry

2004 ◽  
Keyword(s):  
Conducting Polymers ◽  
Liquid Crystalline ◽  
Polymer Chemistry ◽  
Chain Growth ◽  
Crystalline Polymers ◽  
Wide Range ◽  
Cyclic Oligomers ◽  
Step Growth

Polymer Chemistry: A Practical Approach in Chemistry has been designed for both chemists working in and new to the area of polymer synthesis. It contains detailed instructions for preparation of a wide-range of polymers by a wide variety of different techniques, and describes how this synthetic methodology can be applied to the development of new materials. It includes details of well-established techniques, e.g. chain-growth or step-growth processes together with more up-to-date examples using methods such as atom-transfer radical polymerization. Less well-known procedures are also included, e.g. electrochemical synthesis of conducting polymers and the preparation of liquid crystalline elastomers with highly ordered structures. Other topics covered include general polymerization methodology, controlled/"living" polymerization methods, the formation of cyclic oligomers during step-growth polymerization, the synthesis of conducting polymers based on heterocyclic compounds, dendrimers, the preparation of imprinted polymers and liquid crystalline polymers. The main bulk of the text is preceded by an introductory chapter detailing some of the techniques available to the scientist for the characterization of polymers, both in terms of their chemical composition and in terms of their properties as materials. The book is intended not only for the specialist in polymer chemistry, but also for the organic chemist with little experience who requires a practical introduction to the field.

Dense arrays of site-controlled quantum dots with tailored emission wavelength: Growth mechanisms and optical properties

2017 ◽  
Vol 111 (22) ◽  
pp. 221102 ◽  
Author(s):  
Alessandro Surrente ◽  
Marco Felici ◽  
Pascal Gallo ◽  
Alok Rudra ◽  
Benjamin Dwir ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Emission Wavelength ◽  
Growth Mechanisms ◽  
Dense Arrays

General procedures in chain-growth polymerization

2004 ◽  
Author(s):  
Najib Aragrag ◽  
Dario C. Castiglione
Keyword(s):  
Free Radical ◽  
Ring Opening ◽  
Point Of View ◽  
Polymerization Process ◽  
Undergraduate Teaching ◽  
Chain Growth ◽  
Reaction Conditions ◽  
Growth Processes ◽  
Reagent Purity ◽  
Step Growth

This chapter is intended to provide a general introduction to the laboratory techniques used in polymer synthesis, by focusing on some relatively well-known polymerizations that occur by chain-growth processes. In this way some of the more commonly used procedures in polymer chemistry are described. Due to the nature of the intermediates produced, such as free radicals, carbanions, carbocations, together with a range of organometallic species, the techniques often involve handling compounds in the complete absence of oxygen and moisture. Because of this the best results may require quite sophisticated equipment and glassware; however, it is our intention to show that the general procedures are accessible to any reasonably equipped laboratory, and indeed some of the techniques are suitable for use in an undergraduate teaching laboratory. Chain-growth polymerization involves the sequential step-wise addition of monomer to a growing chain. Usually, the monomer is unsaturated, almost always a derivative of ethene, and most commonly vinylic, that is, a monosubstituted ethane, 1 particularly where the growing chain is a free radical. For such monomers, the polymerization process is classified by the way in which polymerization is initiated and thus the nature of the propagating chain, namely anionic, cationic, or free radical; polymerization by coordination catalyst is generally considered separately as the nature of the growing chain-end may be less clear and coordination may bring about a substantial level of control not possible with other methods. Ring-opening polymerizations exhibit many of the features of chain-growth polymerization, but may also show some of the features expected from stepgrowth polymerizations. However, it is probably fair to say that from a practical point of view the techniques involved are rather similar or the same as those used in chain-growth processes and consequently some examples of ring-opening processes are provided here. It is particularly instructive to consider the requirements of chain-growth compared to step-growth processes in terms of the demands for reagent purity and reaction conditions.

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