Preparation and Characterization of Narrowly Distributed Nanogels with Temperature-Responsive Core and pH-Responsive Shell

Abstract

Narrowly distributed spherical core-shell nanogels were prepared by a two-step aqueous dispersion polymerization. Core particles composed of cross-linked temperature-responsive poly(Nisopropylacrylamide) (PNIPAM) were synthesized via aqueous dispersion polymerization and then used as nuclei for subsequent shell addition of pH-responsive poly(4-vinylpyridine) (P4VP). The morphology and structure of the core-shell particles were confirmed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), and the size distribution was determined by dynamic laser light scattering (DLLS). Temperature-and pH-induced volume phase transitions of the latex particles were also investigated by DLLS. The results show that the P4VP shell does not significantly perturb the temperature-induced volume phase transition of the parent core whether P4VP is ionized or not, and the deswelling behavior differs significantly from that of other polyelectrolyte gels within which the ionic groups are randomly distributed.

Multifunctioning pH‐responsive nanoparticles from hierarchical self‐assembly of polymer brush for cancer drug delivery

“…52 Typically, the specimen was prepared as follows. One drop of the nanoparticle solution was applied on a copper TEM grid covered with a very thin carbon film and dried at ambient temperature.…”

Glucose-responsive microgels with a core–shell structure

“…These systems were composed with the well-known temperature-responsive pNIPAM, associated to pNIPAM-co-acrylic acid, which is also sensitive to pH. Other combinations of polymers were further investigated: polymers with different LCST such as poly-N-isopropylmethacrylamide (pNIPMAM) [14] or pNIPAM modified with a hydrophobic monomer, butylmethacrylate [15], and other pHsensitive polymers based on 4-vinylpyridine [16]. These fundamental studies helped elucidating the fine structure of such objects [17,18], as well as understanding the mutual influence of core and shell on thermodynamic and mechanical properties [19,20].…”

Preparation of pH‐Responsive Hydrophilic Core‐Shell Particles for Encapsulation of Water‐Soluble Material

“…[8] Therefore, there have been many reports which have attempted to develop a general understanding of the factors which control the particle morphology. [9,10] Recently, functional-group-incorporated particles with various morphologies have been investigated for further applications, such as environmental stimuli-responsive polymeric hydrogels.…”