Synthesis and characterization of dopamine-modified Ca-alginate/poly(N-isopropylacrylamide) microspheres for water retention and multi-responsive controlled release of agrochemicals

The multi-responsive controlled-release system could enhance crop yield while improving utilization efficiency of agrochemicals, and minimize environmental pollution caused by agrochemicals overuse. This work reports a novel Ca-alginate/Poly( N -isopropylacrylamide)@polydopamine (Ca-alginate/PNIPAm@PDA) microsphere to control the agrochemicals release. Microsphere with a semi-interpenetrating network, which contained pH-sensitive Ca-alginate, temperature-sensitive poly( N -isopropylacrylamide) (PNIPAm), and sunlight-sensitive polydopamine (PDA), was characterized by thermogravimetric analysis , zeta potential , Fourier transform infrared spectroscopy , and scanning electron microscopy to prove the successful synthesis. Moreover, the comprehensive performances, including photothermal conversion, water absorbency, water retention, and controlled-release agrochemicals behaviors, were systematically investigated. The results indicated that the composite microsphere was a prosperous water and agrochemicals manager to effectively retain water and control the release of agrochemicals by external stimulation. Consequently, the Ca-alginate/PNIPAm@PDA microsphere with outstanding water-retention and controlled-release capacities is economical and eco-friendly and thus is promising for utilization as water and agrochemicals controlled-release carrier material in agriculture applications.