Poly(acrylamide-co-2-acrylamido-2-methyl-1-propanesulfonic Acid) Nanogels made by Inverse Microemulsion Polymerization

Abstract

Poly(acrylamide-co-2-acrylamido-2-methyl-1-propanesulfonic acid) poly(AM-co-AMPSA) nanogels were prepared through inverse microemulsion polymerization with low AMPSA/AM weight ratio in the feed (up to 0.3357) to control particle size and pH sensitivity. An aqueous solution of AM and AMPSA was used as the dispersed phase for microemulsion with sodium bis(2-ethylhexyl) sulfosuccinate (AOT)/Toluene solution as the dispersion medium. The polymerization was carried out at 50 • C in the presence of 2,2-azobisisobutyronitrile (AIBN) and N,N -methylenebisacrylamide (NMBA) as an initiator and a crosslinker, respectively. Fourier transform infra red spectrophotometer (FTIR) and 1 H-nuclear magnetic resonance spectroscopy ( 1 H-NMR) studies confirm the occurrence of copolymerization between the two monomers. The hydrodynamic diameter of synthesized poly(AM-co-AMPSA) nanogels is found to be in the range of 63-125nm as measured by dynamic light scattering (DLS). The equilibrium swelling and the effect of pH on particle size of copolymer nanogel are found to depend on the copolymer composition. The polymer chain composition, thermal properties and morphology of nanogels were measured by elemental analysis, thermogravimetric analyzer (TGA) and differential scanning calorimeter (DSC), and scanning electron microscope (SEM), respectively.

Untreated Silica Nanoparticles Containing Poly(acrylamide-co-2-acrylamido-2-methyl-1-propanesulfonic acid) Composite—Effect of Copolymer Composition

“…Hence, the present TEM micrographs of copolymer composites are in concordance with our previous SEM results of copolymers [38] . The high dose of AMPSA in the copolymer composites repeats the shape similar to that of copolymer nanogels [38] .…”

The Influence of Initiator Concentration on Selected Properties of Thermosensitive Poly(Acrylamide-co-2-Acrylamido-2-Methyl-1-Propanesulfonic Acid) Microparticles

“…The ATR-FTIR spectra of the monomer–2-acrylamido-2-methyl-1-propanesulfonic acid (AMPSA), the initiator–potassium persulfate (KPS), and synthesized PS1, PS2, PS3, and PS4 homopolymers in the transmittance mode are presented in Figure 5 . Both the monomer spectrum and the sample spectra contain strong bands assigned to C=O stretching vibrations of the amide group at 1664 cm −1 (AMPSA) and 1641 cm −1 (PS1–PS5) and the N-H bending vibrations, appearing in all cases at the same wavelength of 1550 cm −1 [ 29 , 30 , 31 ]. Moreover, the spectrum of AMPSA presents some characteristic peaks: at 3236 cm −1 and corresponding to N-H [ 32 ] stretching vibrations of the amide group, at 3101, 3035, and 1611 cm −1 attributed to H-C=C stretching vibrations of the vinyl group [ 33 , 34 , 35 ] at 1232 and 1076 cm −1 characteristic for the asymmetric and symmetric stretching vibrations of the O=S=O group and additionally at 623 cm −1 assigned to stretching vibrations of the C-S group [ 36 ].…”

“…The signals between δ = 7.99–6.92 ppm belonged to H a protons of the NH group and presumably also to protons derived from the exchange between the amide and sulfonic acid hydroxyl groups [ 43 ]. The δ = 3.3–2.6 ppm shift corresponded to the H e proton from the CH 2 group bonded to the SO 3 H group [ 29 ]. The signal of δ = 1.93 ppm revealed the H h proton of the methylene group in the main chain.…”

Swelling Behavior of Poly(N-isopropylacrylamide) Nanogels with Narrow Size Distribution Made by Semi-continuous Inverse Heterophase Polymerization

“…Crosslinking arises from covalent bonds, hydrogen bonding, van der Waals interactions, and/or physical entanglements (2). The current research of these materials has focused in preparing nanogels, which are polymer gels with dimensions in the range of ten to a few hundred nanometers, for specific applications in nanoscience and nanotechnology (3). Nanogels have been attracted attention recently for their advanced applications, i.e., in targeting radiopharmaceuticals (4), field emissive displays, cathode ray tube (5) and recently, as smart materials that respond external stimuli (6).…”