Inter/Intramolecular Interaction and Chiral Recognition of Water-Soluble Copolymers and Their Hydrogels Containing an Optically Active Group

Abstract

Aqueous solutions of copolymers, consisting of N-isopropylacrylamide (NIPA) and optically active N-acryloyl-l-alanine (NALA) (poly(NIPA-co-NALA)), exhibited phase-separation temperatures (cloud point, T c), and they were soluble at the lower temperatures and phase-separated at the higher temperatures. The T c decreased with increasing NALA composition and increased with increasing pH of the solutions. The results of T c measurements in the presence of NaCl and a urea derivative and Fourier transform infrared measurements with a curve-fitting method indicated that an increase in the composition of NALA in the copolymers induced hydrogen bonding in and between the copolymer chains. The partition coefficient (K) and diffusion coefficient (D) of R- and S-[1-(dimethylamino)ethyl]ferrocene (DMAEFc) in poly(NIPA-co-NALA) gels in aqueous solutions were estimated by a membrane permeation method. Negligible difference was observed for K between R- and S-DMAEFc; however, D of R-DMAEFc became smaller than that of S-DMAEFc when the gels started to collapse.

Importance of bound water in hydration–dehydration behavior of hydroxylated poly(N-isopropylacrylamide)

“…Schild reviewed some physicochemical studies concerning the PNIPAAm in order to understand its phase transition mechanism [7]. Moreover, many researchers have investigated the unique solution properties of PNIPAAm and other thermoresponsive polymers [8][9][10][11][12].…”

Study of Peptide Dendrimers Having a Ferrocene Core Supported on Mercaptoundecanoic Acid

“…In addition, X-ray photon spectroscopy (XPS) was also used to gain information about the elemental composition and film thickness of the dendrimer films. Scheme shows some plausible H-bonding interactions between MUA/MUA, MUA-amide, and MUA-ester. − RAIRS were recorded for MUA-modified gold surfaces and Fc-peptide dendrimers deposited onto MUA-modified gold surfaces. Figure shows the partial RAIRS for the MUA film on Au, which is characterized by an intense absorbance at 1747 cm -1 with a shoulder at 1710 cm -1 .…”

“…The peaks of MUA at 1740 cm -1 is consistent with the CO stretch of non-H-bonded acid groups. The shoulder peak at 1710 cm -1 indicates the presence of a small fraction of face-to-face H-bonded dimers. − Also present is an intense sharp absorbance at 3577 cm -1 and a set of peaks in the 2950−2800 cm -1 region. Although, we are not making any effort in providing a detailed assignment of the signals, it is likely that the band at higher wavenumbers is due to the carboxylate OH (acidic υ(O−H)), whereas the absorptions at lower wavernumbers are most lilely the result of symmetric and asymmetric methylene stretching vibrations.…”

“…This may be due to H-bonding to the carbonyls of the ester. The amide I band appears in the region between 1660 and 1670 cm -1 , whereas the amide II band occurs in the 1535−1590 cm -1 region of the spectrum . Table summarizes the RAIRS signals for all films.…”

Double hydrophilic copolymers – synthetic approaches, architectural variety, and current application fields

“…, complex formation or even stabilising effects to improve solubility. 48,170,251–254 Examples would be the coating, 29 stabilisation, 12,48 or functionalization of inorganic nanoparticles in aqueous media. 15,33,249 DHCs play a significant role here, and are employed in drug and gene delivery, as surfactants, or to support crystallisation.…”