Morphological control of hybrid amphiphilic poly(N-isopropylacrylamide)/metal cyanide complexes

Abstract

A number of amphiphilic N-isopropylacrylamide (NIPAAm) oligomers and polymers with a S-1-dodecyl-Sʹ-trithiocarbonate (DTC) and an amino terminal group were prepared using RAFT polymerization: DTC-NIPAAm 13-NH 3 Cl (1), DTC-NIPAAm 61-NH 3 Cl (2), DTC-NIPAAm 78-NH 3 Cl (3), DTC-NIPAAm 119-NH 3 Cl (4). and DTC-NIPAAm 274-NH 3 Cl (5). Aqueous solutions of 1-5 became cloudy upon heating at pH 10, while 1-4 did not exhibit thermosensitivity at pH 7.0, instead forming stable rods and vesicles in aqueous solution. Nanorods and nanosquares were obtained from metal cyanide complexes of 1 and 2, both of which had low degrees of polymerization, and aqueous solutions of these nanocomposites became cloudy at pH 7.0. The electrostatic interactions between the amine segments and the anionic metal cyanide complexes as well as the low degree of polymerization in the vicinity of approximately 100 were both found to have a significant role in the morphology and thermoresponsiveness of the hybrids. These hybrid NIPAAm oligomer/metal cyanide complexes may allow the design of flexible, functional supramolecular systems in aqueous solutions.

SAXS Evaluation of Size Distribution for Nanoparticles

“…It is because the DLS technique in principle evaluates diffusion constants of particles and all of the grains in the same bunch of grapes diffuse as a whole. Thus, the methodology is important to highlight versatility and diversity in real materials, especially in soft matter, Figure 21 [31,32].…”

“…Kuroiwa et al [31,32] have synthesized novel amphiphilic N-isopropylacrylamide (NIPPAm) oligomers with dodecyl groups and carboxyl groups, as shown in Figure 20a,b yt h eR A F T polymerization of NIPPAm with S-1-dodecyl-S'-(α,α′-dimethyl-α"-acetic acid) trithiocarbonate (DTC). It was interestingly found that the DTC-NIPPAm oligomers form network aggregation upon addition of Cu 2+ ion in an aqueous solution, as revealed by TEM ( Figure 20b for the dried specimen from an aqueous solution of DTS-NIPPAm35 with Cu 2+ ions).…”

Recent developments in polymer applications of synchrotron small‐angle X‐ray scattering

“…In block copolymer microdomain systems, a Gaussian distribution of the particle size has been assumed and no effort for the determination of the discrete size distribution had been made. Only recently, direct determination of the discrete size distribution has been available by fitting the theoretical scattering function to the experimentally obtained SAXS profile (plot of the scattering intensity as a function of q ) where the abundance of particles having a given size was treated as a floating parameter with a step of one nanometer (the step can be more precise) …”