Poly(vinylamine) microgels: pH-responsive particles with high primary amine contents

Abstract

pH-responsive microgels are crosslinked polymer colloid particles that swell when the pH approaches the pK a of the polybase or polyacid chains. Poly(vinylamine) (PVAM) has the highest primary amine content of all amine-containing polymers. Despite much effort the preparation of colloidally stable PVAM microgels is still elusive. Here, we introduce a simple and scalable, two-step method for preparation of pH-responsive PVAM microgels. First, non-aqueous dispersion (NAD) polymerization was used to prepare new monodisperse water-swellable poly(N-vinylformamide-co-2-(N-vinylformamido)ethyl ether microgels (PNVF-xNVEE). Here, x is the mol% of the alkali-stable crosslinker (NVEE) used. Alkali-hydrolysis of the PNVF-xNVEE microgels in water gave colloidally stable poly(vinylamine-co-bis(ethyl vinylamine)ether) (PVAM-xBEVAME) microgel dispersions. SEM images showed that both the PNVF-9NVEE and PVAM-9BEVAME microgel particles had cluster-like morphologies. The PVAM-xBEVAME particles were positively charged at pH values less than 12. The hydrodynamic diameters and electrophoretic mobilities increased strongly as the pH decreased. In order to demonstrate that primary amines could be used as chemical handles for conjugation, pyrene carboxylic acid was coupled using N-(3-dimethylaminopropyl)-N 0ethylcarbodiimide (EDC) chemistry and its presence confirmed by fluorescence microscopy. Because this new family of colloidally stable microgels has very high primary amine contents and was prepared by a scalable synthetic method there should be potential applications in a wide range of areas from surface coatings and new hybrid particles to delivery.

Control of amine functionality distribution in polyvinylamine/SBA-15 hybrid catalysts for Knoevenagel condensation

“…It is noteworthy that after neutralization the intensity of band assigned to the deforming vibrations of protonated amino species strongly decreases. Two new, characteristic bands appeared at 3350 and 3290 cm −1 due to the stretching vibrations of N-H in primary amino groups [25,26]. The unexpected evolution of the bands attributed to stretching vibrations of aliphatic groups in polymer chain -CH and -CH 2 (2935, 2905 and 2845 cm −1 ) is also noticeable.…”

Functionalization of mesoporous SBA-15 silica by grafting of polyvinylamine on epoxy-modified surface

“…The presence of signals due to the stretching mode of methoxy groups (in the region of 2850-2960 cm -1 ) suggests that GPTMS is grafted on the silica surface by less than three R-Si-O-(silica) links. The representative spectrum of PVAm/SBA-15 hybrid material prepared by grafting "onto" shows new absorption bands in the ranges of 1300-1700 and 2800-3400 cm -1 [34,35]. In the high frequency region, peaks at 3290 and 3350 cm -1 indicate the presence of asymmetric and symmetric N-H stretching modes of primary amino groups.…”

Modulating Crystallization in Semitransparent Perovskite Films Using Submicrometer Spongelike Polymer Colloid Particles to Improve Solar Cell Performance

“…New sub-micrometer PNVF-NVEE MGs were prepared by non-aqueous dispersion polymerization using a modification of the method described previously 55 . We discovered that by decreasing the total mass of monomers used by a factor of two compared to the earlier work the MG diameter decreased by a factor of two.…”

“…Water was of ultrahigh purity and de-ionized. NVEE was synthesized and characterized using the methods described previously 55 .…”