Conformational properties of cylindrical rod brushes consisting of a flexible polystyrene main chain and poly(n-hexyl isocyanate) (PHIC) rod side chains have thoroughly been studied by static light and small-angle X-ray scattering (SAXS) in tetrahydrofuran (THF) at 25 °C. These rod brushes were prepared by radical homopolymerization of 4-vinylbenzyloxy-ended PHIC macromonomers (1) (VB-HIC-N s , where N s is the weight-averaged degree of polymerization of HIC and in a range from 21 to 80) in n-hexane at 60 °C. The mean-square cross-sectional radius of gyration (〈R c 2 〉 0 ) of the brush at an infinite dilution is determined by SAXS measurement and rationalized as a function of N s . The experimental value of 〈R c 2 〉 0 gradually increases with N s but above N s higher than 20 increases to follow the scaling law of 〈R c 2 〉 0 ∝ N s 0.87 . The experimental N s dependence of 〈R c 2 〉 0 is compared to that from the wormlike comb model whose main and side chains have different stiffness parameters. The molecular weight dependence of z-averaged mean-square radius of gyration (〈R g 2 〉 z ) of the brush is determined and analyzed in terms of the wormlike cylinder model taking into account the end effects. The parameters characteristic of the rod brush in THF solution, such as the main chain stiffness parameter (λ M -1 ), the molecular weight per unit contour length (M L ), and the excluded-volume strength (B), are determined and rationalized as a function of the contour length of the side rod. The polystyrene main chain stiffness of the rod brush remarkably increases by the densely located rod side chains to follow the scaling law of λ M -1 ∝ N s 1 . The backbone stiffness of the rod brush is higher than that of the flexible brush consisting of flexible polystyrene side chains with the corresponding contour length. A single rod brush of poly(VB-HIC-47) deposited on a mica surface is observed by the scanning force microscopy to reasonably demonstrate the cylindrical rod brushes.

The 2‐chloropropionamide derivative featuring an azido group is used as the initiator for the ATRP of N‐isopropylacrylamide (NIPAM) with copper(I) chloride (CuCl) and tris[2‐(dimethylamino)ethyl]amine (Me6TREN) to produce the PNIPAM end‐functionalized with an azido group. Subsequently, the ‘click’ reaction between the azido end‐group and acetylene derivatives is demonstrated to produce PNIPAM in which the end‐groups are modified by the phenyl, 4‐phenoxyphenyl, butyl, octyl, carboxylic acid, and hydroxymethyl groups. The resulting PNIPAM derivatives show a LCST that ranges from 34.8 to 44.6 °C depending on the introduced end‐group.magnified image

N-Isopropylacrylamide (NIPAM) was polymerized using 1-pyrenyl 2-chloropropionate (PyCP) as the initiator and CuCl/tris [2-(dimethylamino)

This work discusses the self-assembly properties of thermoresponsive hybrid oligosaccharide-block-poly(N-isopropylacrylamide) copolymer systems: maltoheptaose-block-poly(N-isopropylacrylamide) (Mal(7)-b-PNIPAM(n)) copolymers. Those systems at different molar masses and volume fractions were synthesized using Cu(I)-catalyzed 1,3-dipolar azide/alkyne cycloaddition, so-called "click" chemistry, between an alkynyl-functionalized maltoheptaose (1) and poly(N-isopropylacrylamide) having a terminal azido group (N(3)-PNIPAM(n)) prepared by atom transfer radical polymerization (ATRP). While the cloud point (T(cp)) of the N(3)-PNIPAM(n) ranged from 36.4 to 51.5 degrees C depending on the degree of polymerization, those obtained of the diblock copolymers ranged from 39.4 to 73.9 degrees C. The self-assembly of such systems is favored due to the hydrophobicity of the PNIPAM in water above the T(cp). While the N(3)-PNIPAM(n) present polydisperse globular shape with a mean diameter of 500 nm, well-defined vesicular morphologies with an approximate diameter of 300 nm are obtained in diblock copolymer systems. These results were obtained and confirmed using static and dynamic light scattering as well as imaging techniques such as transmission electron microscope experiments.

The core-first synthesis of three-, four-, and six-armed star-shaped poly(methyl methacrylate)s (PMMAs) with predicted molecular weights and narrow molecular weight distributions (M w /M n s) was carried out by the t-Bu-P 4 -catalyzed group transfer polymerization (GTP) of methyl methacrylate (MMA) using the newly designed silyl enolates, such as 1,1,and bis{2,2,2-tris[2-methyl-1-(trimethylsilyloxy)prop-1-enyloxy]ethyl}ether (O-(C(MTS) 3 ) 2 ), respectively. The absolute molecular weight (M w (MALS)) of the obtained polymers proportionally increased with the increasing [MMA] 0 /[initiator] 0 ratio, and the highest molecular weight was ca. 132 kg mol À1 . Characterizations for the star-shaped PMMAs were conducted by cleavage and intrinsic viscosity [η] experiments. Cleavage experiments of the star-shaped PMMAs provided the evidence for homogeneous growth of the each arm in the t-Bu-P 4 -catalyzed GTP.The number of arm determined from the shrinking factors (g 0 ) of [η] also supported the successful syntheses of the star-shaped polymers by the present core-first method. The versatility of this core-first method toward other methacrylic monomers was confirmed by the t-Bu-P 4 -catalyzed GTPs of allyl methacrylate (AMA), stearyl methacrylate (SMA), and 2-(dimethylamino)ethyl methacrylate (DMAEMA) using C(MTS) 4 as an initiator leading to well-defined star-shaped polymers.