Preparation and Physicochemical Characteristics of Thermo-Responsive Emamectin BenzoateMicrocapsules.

Yan Wang,Fei Gao,Haixin Cui,Bo Cui,Yue Shen,Zhanghua Zeng,Changjiao Sun,Xiang Zhao

doi:10.3390/polym9090418

Abstract

Thermo-responsive release emamectin benzoate microcapsules were successfully prepared with a polydopamine (PDA)-g-poly(N-isopropylacrylamide) (PNIPAm) multifunctional layer. Preparation of emamectin benzoate microcapsules was first studied by emulsion interfacial-polymerization using PDA as a wall material. Then the amino-terminated PNIPAm was grafted on the PDA layer by its amino group in aqueous solution. Physicochemical characterization of microcapsules was obtained by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and dynamic light scattering (DLS). Kinetic study of emamectin benzoate release showed that the microcapsules exhibit sustained- and controlled-release properties. The multifunctional layer can release emamectin benzoate easily when the temperature was below the lower critical solution temperature (LCST). In contrast, when the temperature increased above the LCST, the release rate was reduced. The results indicated that these microcapsules with excellent thermo-sensitivity would be promising in the research field of pesticide microcapsules.

Highlights

In the past few decades, stimuli-responsive release technology has obtained a growing scientific interest worldwide and attracted considerable attention [1]
Self-polymerization self-polymerization ofofdopamine pH-induced oxidation occurred on the water-oil interface to form the outer shell of microcapsules at room temperature
PNIPAm-g-PDA stimuli-responsive release microcapsules were successfully prepared through multifunctional layer formed by the innerinner film film and a facile and and generalized generalizedapproach

Summary

Introduction

In the past few decades, stimuli-responsive release technology has obtained a growing scientific interest worldwide and attracted considerable attention [1]. The substitution of stimuli-responsive release systems for conventional agrochemical formulations helps to avoid the use of excess amounts of active ingredients, and offers ecologic and economic advantages [7]. Among these technical solutions, controlled-release pesticides formulation is satisfying for obtaining the most effective use of pesticide and reducing environmental pollution [8,9]. These formulations are classified into four different forms: microspheres, microcapsules, matrices with physical-trapped pesticides, and polymers with covalently bound pesticides [1,10]. Microencapsulation is a generalized technology in Polymers 2017, 9, 418; doi:10.3390/polym9090418 www.mdpi.com/journal/polymers

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Results

Conclusion