Evaporation-Induced Crystal Nucleation and Morphology of Dried Poly(Vinylidene Fluoride) Droplets

Crystals

Susu Wang¹  Yongri Liang² 

[1] College of Materials Science and Engineering, Beijing Institute of Petrochemical Technology, Beijing 102617, China;State Key Lab of Metastable Materials Science and Technology, School of Materials Science and Engineering, Yanshan University, No. 438 West Hebei Avenue, Qinhuangdao 066004, China;

关键词: evaporation;    poly(vinylidene fluoride);    crystallization;    droplet;    coffee ring effect;    ultrasonic spray;   

DOI  :  10.3390/cryst11121442

来源: DOAJ

【 摘 要 】

The evaporation of a polymer solution droplet is important in solution-based polymer film fabrications, such as inkjet printing, spray coatings, and droplet casting, etc. In this work, we investigated the effect of droplet size, solvent evaporation rate, and concentration on the “coffee-ring” effect, crystal nucleation, polymorphism, and morphology of dried poly(vinylidene fluoride) (PVDF) solution droplets with the atomic force microscopy (AFM) and two-dimensional grazing incidence wide angle X-ray scattering (2D GIWAXS) method. We found that the crystal structure, morphology and crystal distribution in the center and edge regions of dried PVDF droplets were different due to the “coffee-ring” effect. The “coffee-ring” effect of dried PVDF droplets was mainly composited of accumulated crystals at the edge region of a droplet, which was mainly made by the crystallization of migrated chains. The interplay between the migration of chains and the crystallization and solidification of PVDF droplets significantly influenced the formation of the “coffee-ring”. In addition, our results showed that the decrease in droplet size and the controlling solvent evaporation rate were effective ways to improve the electroactive crystalline phases (β and γ-phases) nucleation and decrease the crystal size.

【 授权许可】

Unknown