Preparation and Modification of Poly(methacrylic acid) and Poly(acrylic acid) Multilayers

Abstract

By employment of a strategy of post-transfer modification, precursor Langmuir-Blodgett (LB) films of poly(tert-butyl methacrylate) (PtBMA) and poly(tert-butylacrylate) (PtBA) can be converted to poly-(methacrylic acid) (PMAA) and poly(acrylic acid) (PAA) through acid-catalyzed hydrolysis in the gas phase. X-ray reflectivity studies show that these films possess surface roughnesses and controllable thicknesses, which are consistent with the retention of the "two-dimensional" configuration of the precursor polymers at the air/water interface. On this basis, the PMAA and PAA films with presumable layered architecture can be obtained, even though PMAA and PAA are too hydrophilic to undergo direct LB-multilayer formation. A combination of infrared spectroscopy, contact angle measurements, and sorption experiments confirms the chemical transformation and increased hydrophilicity of the films. Using the same approach, gasphase reactions with organic amines convert the reactive carboxylic acid groups to their corresponding ammonium salts, thereby leading to the formation of polyelectrolyte LB films. When these films are heated to elevated temperatures, amide bonds are formed. The use of difunctional amines opens up the possibility to cross-link the PMAA or PAA films efficiently. Fourier transform infrared measurements and X-ray reflectivity studies clearly indicate the conversion from PtBMA or PtBA LB films to ultrathin, highly swellable network films.

Dendritic growth of poly(ε‐caprolactone) crystals from compatible blends with poly(t‐butyl acrylate) at the air/water interface

“…In the present study, PCL is blended with amorphous poly( t ‐butyl acrylate) (PtBA). The choice of PtBA reflects the fact that PtBA can be spread to form stable liquid‐condensed Langmuir monolayers (monomer thick) at the A/W interface, and PtBA monolayers have the appropriate viscoelastic properties to form Langmuir–Blodgett films 54, 55. The compatibility and rigidity of these blends in the monolayer regime is analyzed through the Wilhelmy plate technique and BAM.…”

All‐Dry Synthesis and Coating of Methacrylic Acid Copolymers for Controlled Release

“…Quantitatively, the fractions of MAA and EA in the copolymers (F A and F B ) were determined by first resolving the carbonyl ester absorption into two separate peaks using a fitting program, GRAMS A/I (Thermo Galactic), corresponding to the MAA C --O stretch at $1 700 cm À1 and the EA C --O stretch at $1 735 cm À1 . [13,14] The relative areas of the two peaks in the Eudragit copolymer were taken to represent a 1:1 MAA/EA ratio against which the ratios in the iCVD copolymers were then derived. Interestingly, when the peak position of the EA C --O stretch was plotted against F B [ Figure 1(g)], a systematic shift of the peak position can be observed.…”

PAN composite membrane with different solvent affinities controlled by surface modification methods

“…The next possible reaction is a dehydration of the ammonium salts with the formation of secondary amide linkages 31, 32. The presence of the amide I band at 1650 cm −1 in the spectrum corresponding to the PAN membrane after the reaction with EDA 1 h at 50 °C and a heating of 1 h at 110 °C can be observed in Figure 1.…”