Fast and facile one-step synthesis of monodisperse thermo-responsive core–shell microspheres and applications

Abstract

Highly monodisperse PMMA microspheres covered with thermo-responsive shell were synthesized in a single step by means of photoinitiated RAFT dispersion polymerization at room temperature. Thermo-responsive Macro-RAFT agents (P(mPEGA-co-MEA)-TTCs) with different lower critical solution temperatures (LCST) were used as stabilizers in the process.Particle yields of over 95% were achieved within 45 min of UV irradiation, showing a fast process. The microspheres obtained were well-dispersed in water at a temperature below the LCST, and precipitated from the aqueous dispersion at a temperature above the LCST, exhibiting a reversible thermo-responsive property. The particle size can be precisely controlled by adding the monomer to the reaction in batches, and the microspheres maintained their high uniformities during the reaction. The thermo-responsive PMMA microspheres can be effectively conjugated to proteins via the carboxyl groups on the Macro-RAFT chains. A thermo-responsive PMMA/ZIF-8 core-shell structure was also synthesized by using P(mPEGA-co-MEA)-b-PAA stabilized PMMA microspheres as the template, and exhibited good adsorption properties for methyl blue.

Photomediated controlled radical polymerization

“…particles with thermoresponsive properties based on PEGA and methoxyethyl acrylate. [241] The concept was also suitable for synthesis of metal-composite particles, [238,240] or particles suitable for bioconjugation via 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) coupling. [242] In a similar procedure monodisperse microparticles were obtained by direct photoRAFT of crosslinking monomers.…”

Facile Preparation of CO2‐Responsive Polymer Nano‐Objects via Aqueous Photoinitiated Polymerization‐Induced Self‐Assembly (Photo‐PISA)

“…Stimuli‐responsive polymer nano‐objects have attracted much attention due to their broad applications in a variety of areas such as nanoreactor, molecule separation, bioimaging, and nanomedicine . To date, numerous external signals including light, temperature, and electric field, as well as physiological factors, such as pH, enzyme concentration, and redox potential have been explored for the synthesis of responsive polymer nano‐objects. In particular, carbon dioxide (CO 2 ) response is one of the most exciting stimulus, which can apply to physiological environment.…”

Carboxyl-Functionalized Polymeric Microspheres Prepared by One-Stage Photoinitiated RAFT Dispersion Polymerization

“…Organic/inorganic composite microspheres with narrow particle size distributions have attracted considerable attention due to the broad applications in catalysis, energy storage, and water treatment [ 12 , 38 , 39 , 40 ]. As a proof-of-concept experiment, Ag composite microspheres were prepared by in situ reduction of AgNO 3 using the carboxyl-functionalized polymeric microspheres as the template.…”