مقاله انگلیسی رایگان در مورد نانو سیم های پلیمری متصل شده توسط تنظیم تعامل بین حلال و پلیمر – الزویر 2018

Conjugated polymers have been extensively researched due to their good electronic properties and solution processing advantages in field-effect transistor (FET) and solar cells [1e5]. The charge transport in conjugated polymer thin films is influenced by the condensed matter such as molecular planarity, p-p stacking distance, crystallinity and long range order [6e11]. High crystallinity conjugated polymer nanowires provide the high long-range order of polymer chains and higher field-effect carrier transport [12e14]. The formation of nanowires in solution is generally considered to go through nucleation and growth process. The essential driving force for crystallization from solution relies on the degree of supersaturation. Conjugated polymer nanowires can be prepared by solubility difference, such as self-seeding method by changing the solution temperature [15e17], whisker method by aging the solution at selected solvent and temperature [18e21] and solvent slow evaporation [22e24]. The length of these nanowires was 10e100 mm and the width was more than 100 nm. Although many kinds of conjugated polymer nanowires have been prepared successfully at special solvent and temperature, the general principle for choosing solvent to prepare the nanowire in solution with higher density needs further investigate. At a higher concentration, the solution becomes further supersaturated, where nucleation dominates crystal growth, and most of the excess solute becomes subject to spontaneous nucleation which is not beneficial for the growth of nanowires. Conjugated polymer chain aggregation in solution prior to film fabrication is critical for their film structure. Solubility parameters are certain measurable quantities that are observed to influence the ability of a solvent to dissolve a polymer. The solvent selection principle of disentanglement could be proposed based on the Hansen solubility parameter and the radius of interaction (Ra) between the solvent and polymer. Ra is defined as the distance between the solvent and polymer solubility parameter in Hansen space, by the following equation: ðRaÞ 2 ¼ 4ðdD2 dD1Þ 2 þ ðdP2 dP1Þ 2 þ ðdH2 dH1Þ 2 (1) where dD2, dP2 and dH2 are the Hansen parameters of the solvent, dD1, dP1 and dH1 are the Hansen parameters of the polymer. The Ra could tune the solubility and supersaturation. The solubility is increased to facilitate disentanglement with decreasing Ra. The supersaturation is the driving force of crystallization and could control the nucleation rate and growth rate. The aggregation of polymer could be governed by solubility parameter [25e31]. According to the solvent selection principle, the nanowires could be prepared in non-chlorinated solvents [32], this could avoid the use of chlorinated solvents in current literature.