A hollow mesoporous silica and poly(diacetone acrylamide) composite with sustained-release and adhesion properties

Abstract

Controlled release formulation of pesticides is a highly desirable way to increase the efficiency of the pesticide as well as help reduce environmental pollution issues. In the present study, a novel adhesive organic-inorganic hybrid material with a uniform size and morphology was fabricated employing hollow mesoporous silica (HMS) as an inlayer material and poly(diacetone acrylamide) (PDAAM) as an outer layer material. HMS was fabricated using polystyrene (PS) spheres as a hard template. Then, HMS was functionalized with 3-aminopropyltriethoxysilane and 2-bromoisobutyryl bromide after removal of PS. Finally, PDAAM was grafted onto HMS using surface-initiated atom transfer radical polymerization. Cyantraniliprole (CNAP) utilized as a model pesticide was incorporated into hybrid material to prepare controlled release formulation. The results showed that both CNAP−loaded HMS and HMS−PDAAM had extraordinary loading efficiencies (approximately 50% w/w). Kinetic studies of CNAP release demonstrated that CNAP−loaded HMS−PDAAM exhibited a sustained release property for at least 25 days. The stability test identified that CNAP−loaded HMS and HMS−PDAAM were much more stable under UV irradiation and thermal conditions than CNAP technical. Tests of the adhesive properties showed that the adhesive property of HMS−PDAAM was far stronger than that of HMS on rice leaves. Given the advantages of HMS−PDAAM, this hybrid material may be applied to other photosensitive pesticides, especially those used for foliar spraying.