A Near-Infrared and Temperature-Responsive Pesticide Release Platform through Core–Shell Polydopamine@PNIPAm Nanocomposites

Abstract

Controlled stimuli-responsive release systems are a feasible and effective way to increase the efficiency of pesticides and help improve environmental pollution issues. However, near-infrared (NIR)-responsive systems for encapsulation of pesticides for controlling release have not been reported because of high cost and load ability of conventional NIR absorbers as well as complicated preparation process. Herein, we proposed polydopamine (PDA) microspheres as a photothermal agent owing to their abundant active sites, satisfactory photothermal efficiency, low cost, and easy fabrication, followed by capping with a PNIPAm thermosensitive polymer shell. In this core-shell PDA@PNIPAm hybrid system, the PDA core provided excellent temperature and NIR-light sensitivity as well as high loading capacity, while the PNIPAm applied as both a thermosensitive gatekeeper and a pesticide reservoir. The structure of the PDA@PNIPAm nanocomposites was characterized by transmission electron microscopy, scanning electron microscopy, Fourier transform infrared spectroscopy, ultraviolet-visible spectroscopy, dynamic light scattering, and thermogravimetric analysis; the results showed that the nanocomposites had a well-defined core-shell configuration for efficient loading of small pesticide molecules. Moreover, the core-shell PDA@PNIPAm nanocomposites exhibited high loading capacity and temperature- or NIR-controlled release performance. Overall, this system has significant potential in controlled drug release and agriculture-related fields as a delivery system for pesticides with photothermal responsive behavior.

Green Formation of Robust Supraparticles for Cargo Protection and Hazards Control in Natural Environments

“…The mechanisms of cargo delivery were identified by fitting the release profiles to kinetic models . Elovich and Korsmeyer–Peppas models described the thymol release reasonably well, but the Elovich model was used to fit the cargo release profile from the SPs, as it provided the best coefficients of determination (over 0.95; Table S1, Supporting Information).…”

“…The mechanisms of cargo delivery were identified by fitting the release profiles to kinetic models. [36][37][38][39][40] Elovich and Korsmeyer-Peppas models described the thymol release reasonably well, but the Elovich model was used to fit the cargo release profile from the SPs, as it provided the best coefficients of determination (over 0.95; Table S1, Supporting Information). Elovich fit indicated that the cargo fraction delivered over time (with k being the release rate) decreased proportionally to the fractions already released, characteristic of a logarithmical time-dependent behavior.…”

Thermosensitive Hydrogel for Encapsulation and Controlled Release of Biocontrol Agents to Prevent Peanut Aflatoxin Contamination

“…Temperature-sensitive hydrogels have comprehensive applications in the controlled release of drugs, tissue culture, and the immobilization of protein [22][23][24]. In agriculture, temperature-responsive polymers have been investigated as pesticide carriers, as the release rate can be controlled to meet the requirements of pest prevention [25,26]. Poly(N-isopropylacrylamide) (PNIPAAm) is a typical temperature-responsive polymer, exhibiting a temperature-dependent volume phase transition near the lower critical solution temperature (LCST) in aqueous solution [27,28].…”

Sunlight Induced Rapid Oil Absorption and Passive Room‐Temperature Release: An Effective Solution toward Heavy Oil Spill Cleanup

“…In recent years, stimuli-responsive absorbents with switchable wettability offer an effective means to absorb and subsequently passively recover oil under external stimuli, such as pH, [15][16][17][18][19][20] heat, [21] and UV irradiation [22,23] . Among the stimuli-responsive materials, temperature/heat-based switchable material is an interesting case [21,[24][25][26][27][28][29][30] because of the availability of various direct and indirect heat energy sources, including hot/cold water, electricity used to locally generate heat by Joule heating mechanism. Freely and widely available is another ubiquitous energy source, sunlight, which can be readily harvested and converted to heat by a myriad of solar-thermal materials, [31][32][33][34][35] for instance, metals, [32] carbonbased materials, [33,34] and polymers [35] .…”