resumo
Hypothesis: Reversible addition fragmentation chain transfer (RAFT) - assisted encapsulating emulsion polymerization (REEP) has received considerable attention as an efficient strategy to prepare colloidal stable shell@core nanoparticles. Generally, amphipathic macroRAFT agents are used but the effect of working above or below the critical micelle concentration (CMC) of macroRAFT agents needs to be addressed. Hence, it is necessary to understand if this parameter has an impact not only on the stability of the colloids but also on the molecular mass of the polymer shell. Methods: Here, the CMC of three different macroRAFT agent was determined and the effect of macroRAFT agents concentration on the colloidal stability of gold nanoparticles coated with macroRAFT agents (macroRAFT@Au) assessed. The subsequent chain extension from macroRAFT@Au NPs, resulting in encapsulated Au nanoparticles (copolymer@Au), has also been systematically studied. Findings: Using the REEP approach it was possible to obtain stable encapsulated Au NPs. Moreover, this strategy opens the possibility of adjusting the macroRAFT agents concentration to tune the length of the polymer chains grown around Au cores which is of major interest for the design of biosensors based on responsive polymer shells, such as pH, temperature and photoluminescence quenching. (C) 2019 Elsevier Inc. All rights reserved.
palavras-chave
TUNING THERMORESPONSIVE BEHAVIOR; GOLD NANOPARTICLES; DIBLOCK COPOLYMERS; CARBON NANOTUBES; DRUG-DELIVERY; RAFT; OXIDE; PARTICLES; SIZE
categoria
Chemistry
autores
Pereira, SO; Trindade, T; Barros-Timmons, A
nossos autores
Ana Margarida Madeira Viegas de Barros Timmons
Professor associado
Sónia Oliveira Pereira
Bolseiro de investigação
Tito Trindade
Professor Catedráticoagradecimentos
This work was developed in the scope of the project CICECO-Aveiro Institute of Materials, POCI-01-0145-FEDER-007679 (FCT Ref. UID/CTM/50011/2019), financed by national funds through the FCT/MEC and when appropriate co-financed by FEDER under the PT2020 Partnership Agreement. S. O. Pereira thanks FCT for her PhD grant SFRH/BD/80156/2011. The authors appreciate the funding of the transnational project Encircle (IUPAC/0001/2009) and the Rede Nacional de Microscopia Electronica at University of Aveiro. The authors are grateful to Professor Amilton Santos from the Engineering School of Lorena-USP/Brazil for the GPC analyses of macroRAFT agents.