Polymer-based and stimulus-responsive carriers for controlled release of agrochemicals

Food demand has been increasing substantially world-wide with the growth of population and the depletion of arable land. To increase food production, it is necessary to improve the efficiency of agrochemicals usage while reducing their negative impact on the ecosystem. The controlled release of agrochemicals has been regarded as an emerging technology and critically important strategy to improve the efficiency and performance of agrochemicals. Among various carriers, the stimulus-responsive polymer-based carriers provide the controlled release of agrochemicals based on changes in environmental conditions (such as pH, redox, light, enzymes, etc.) along with preserving the environmental friendliness and affinity particularly for those originating from bioresources. Here, we review the development and application of polymers in the sustained release of agrochemicals. Additionally, the preparation methods and responsive behaviors and mechanisms of stimulus-responsive polymer-based carriers, and the characteristics and advantages of those smart carriers are discussed. However, given the fact that the relevant research is still in its infancy, the large-scale application in farmlands still requires tremendous and continuous efforts to be paid by researchers.