Controllable Catalytic Activity of Temperature-Responsive Polymer Hybrid Microgels Designed Using a Gold Nanoparticle Monomer with Polymerizable Groups

Effect of Gold Nanoparticle Size on Regulated Catalytic Activity of Temperature-Responsive Polymer−Gold Nanoparticle Hybrid Microgels

“…Therefore, the higher catalytic activity of the hybrid microgels with smaller AuNP sizes is a ributed to the fact that the increased surface area allows for a more efficient adsorption of 4-NP onto the AuNP surface and that AuNPs with a smaller size have more active sites because their reduced dimensions correspond to lower coordination numbers [59,62,63]. The catalytic activity of the hybrid microgels with a small AuNP size at temperatures lower than 35 °C was relatively high compared to the AuNP hybrid assemblies reported previously [55]. This might be a ributed to the fact that the hybrid microgels have highly swollen networks and that 4-NP can easily approach the AuNP surface owing to their high permeability (Figure 6).…”

“…According to the method reported in our previous paper [ 55 ], AuNP monomers were prepared by attaching hydrophobic polymerizable acryloyl and hydrophilic carboxyl groups to the AuNP surface ( Scheme S2 ). First, DUDP with two acryloyl groups was synthesized as a thiol to introduce polymerizable groups onto the surface of AuNPs ( Scheme S3 ).…”

“…In a previous paper, we proposed a new method to prepare temperature-responsive polymer–AuNP hybrids using an AuNP monomer with polymerizable groups [ 55 ]. The resulting PNIPAAm–AuNP hybrid microgels switched their catalytic activity upon changing their temperature.…”

“…The preparation of citrate-AuNPs of various sizes exhibited good reproducibility through the careful control of a few crucial factors, but more careful control of the preparation conditions is required for practical applications and scalability. According to the method reported in our previous paper [55], AuNP monomers were prepared by a aching hydrophobic polymerizable acryloyl and hydrophilic carboxyl groups to the AuNP surface (Scheme S2). First, DUDP with two acryloyl groups was synthesized as a thiol to introduce polymerizable groups onto the surface of AuNPs (Scheme S3).…”

“…In general, while PNIPAAm covalently binds to the AuNP surfaces in the PNIPAAm–AuNP hybrids prepared using the first and second methods, AuNPs are physically entrapped within the PNIPAAm networks in the hybrids prepared using the third method. Unlike their standard method, our previous study proposed a simple method to prepare PNIPAAm–AuNP hybrids in which AuNPs are covalently linked with microsized PNIPAAm networks [ 55 ]. This method uses an AuNP monomer with polymerizable groups.…”