Surface Analytical Study of Poly(acrylic acid)-Grafted Microparticles (Beads): Characterization, Chemical Derivatization, and Quantification of Surface Carboxyl Groups

Abstract

We report a surface analytical study of poly(methyl methacrylate) (PMMA) microparticles (beads) with a grafted shell of poly(acrylic acid) (PAA) with thicknesses up to 4 nm using scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), time-offlight secondary ion mass spectrometry (ToF-SIMS), and nearedge X-ray adsorption fine structure (NEXAFS) spectroscopy. These polymer microparticles were analyzed before and after reaction of the surface carboxyl (CO 2 H) groups with 2,2,2trifluoroethylamine (TFEA) to gain a better understanding of methods with use of covalently bound probe molecules for surface group analysis. The results obtained with chemical derivatization XPS using TFEA are discussed in terms of surface quantification of reactive CO 2 H groups on these PAA-coated microparticles. A labeling yield of about 50% was found for TFEA-derivatized particles with amounts of surface-grafted CO 2 H groups of 99 μmol/g or more, which is consistent with predicted reaction yields for homogeneously dispersed PAA hydrogels.

Quantification of amine functional groups on silica nanoparticles: a multi-method approach

“…Despite the wide range of methods, surface group quantication is still challenging; in some cases only qualitative identication of the surface groups is carried out and it is still uncommon to use multiple methods and validated protocols. 2,18,19 Depending on the ultimate application of the nanomaterial, it may be important to be able to detect and identify the surface group and to understand the number of groups on the surface and their overall spatial distribution.…”

“…[21][22][23] In the present study we compare the results from two colorimetric assays for quantication of accessible surface amines to results obtained by labeling amines with tri-uoromethylated probes that provide high sensitivity for XPS and quantitative solid state 19 F NMR. 2,5,19,24,25 The two colorimetric assays are based on the reaction of ninhydrin with primary amines to generate a dye that is released from the surface and quantied in the supernatant and the reaction of an aldehyde with surface amines to generate an imine product that can be cleaved for quantication aer isolation of the NPs. These two assays may differ in their ability to detect surfaceaccessible amines, particularly at high surface coverage where steric effects are expected to become important.…”

Synthesis of Controllable Carboxylated Polystyrene Microspheres by Two-Step Dispersion Polymerization with Hydrocarbon Alcohols

“…It can be considered that Figure 9: FTIR spectra of PS microspheres prepared in different solvents with limit concentration of acrylic acid. 6 International Journal of Polymer Science lower solvent polarity is related to the weakened influence of the PAA segment on the precipitation of the PS-PAA copolymer; thus, the PAA content can be further increased. Table 6 is the molecular weight of PS microspheres synthesized in different solvents with limit concentration of acrylic acid, and this result can also confirm the above conclusions.…”

“…Carboxylated microspheres are often used in biomedical and diagnostic fields such as drug delivery, sensors, and biological detection. For example, polypyrrole-coated PS particles are used to adsorb proteins as a new diagnostic material [6][7][8][9][10].…”

Direct characterization of polymer encapsulated CdSe/CdS/ZnS quantum dots

“…Although polymer encapsulated QDs have been widely used, there are few detailed experimental studies that directly quantify and characterize the interaction mechanism of the adsorbed polymer [22; 30; 31]. It should be noted that many theoretical analyses in the literature are typically based on simple geometric models that presume an interaction mechanism between the polymer and QD.…”