Aminopropyi-heptasobutyl POSS (NH 2 C 3 H 6 POSS) was purchased from Hybrid Plastics. All other materials were purchased from available suppliers (Sigma-Aldrich, TCI, Fisher Scientific, etc.) and used without further purification unless otherwise noted. Tetrahydrofuran (THF) was distilled over sodium naphthalenide and degassed at 10 −6 Torr. Hexane was distilled over 1,1diphenylhexyllithium and degassed at 10 −6 Torr. Lithium chloride (LiCl) was dried with stirring at 150 °C for 24 h at 10 −6 Torr. A 1.4 M sec-butyllithium (s-BuLi) solution in cyclohexane was degassed, appropriately diluted in hexane, divided into clean glass ampules equipped with breakseals at 10 −6 Torr, and stored at −30 °C. 1,1-Diphenylethylene (DPE) and benzyl methacrylate (BzMA) were distilled over calcium hydride (CaH 2 ) at reduced pressure and then redistilled over CaH 2 at 10 −6 Torr. DPE, LiCl, and BzMA were appropriately diluted in THF, divided into clean glass ampules equipped with break-seals at 10 −6 Torr, and stored at −30 °C. A Grubbs third generation catalyst, Ph-CH=Ru(Cl) 2 (H 2 IMes)(pyridine) 2 (G3), was prepared according to a previously reported procedure. S1 S.1.2. Instruments and Analyses.Proton and carbon-13 nuclear magnetic resonance ( 1 H and 13 C NMR) spectra were recorded using a JNM-ECX 400 NMR spectrometer (JEOL) in chloroform-d (CDCl 3 , 99.8% atom D, contains 0.03 vol% tetramethylsilane (TMS)) at 25 °C. Number-average molecular weight (M n ) and dispersity (Ɖ) values of the polymers were measured using a size exclusion chromatographymultiangle laser light scattering (SEC-MALLS) equipped with a 515 HPLC pump (Waters), a set of four Styragel columns connected in series (HR 0.5, HR 1, HR 3, and HR 4 with pore sizes of

A facile and efficient synthetic grafting-through strategy for preparing well-defined bottlebrush block copolymers (BBCPs) was developed through a combination of living anionic polymerization (LAP) and ring-opening metathesis polymerization (ROMP). ω-End-norbornyl polystyrene (NPSt) and poly(4-tert-butoxystyrene) (NPtBOS) were synthesized by LAP using terminator of chlorine moiety containing silane-protecting amine and coupled with a subsequent amidation using norbornyl activated ester. Bottlebrush homopolymers of NPSt were obtained by ROMP with ultrahigh molecular weights (MWs, M w = 2928 kDa) and narrow molecular weight distributions (MWDs, Đ = 1.07) at high degree of polymerizations (DP w = 1084). Welldefined BBCPs with ultrahigh MWs (M w ∼ 3055 kDa) and narrow MWDs (Đ ∼ 1.13) were synthesized through sequential ROMP of NPSt with NPtBOS. The effect of ultrahigh MWs was investigated by self-assembly of the BBCPs in which the phaseseparated BBCPs presented periodic lamellar structures and exhibited structural colors from blue to pink.

We report the propagation-inspired initiation of sodium N-phenethyl-3-phenylpropanamide (NaPEPPA), an aliphatic sodium amidate, for the living anionic homo-and copolymerization of isocyanates. This initiator was compared with sodium benzanilide (NaBA), an aromatic sodium amidate, in the living anionic homopolymerization of n-hexyl isocyanate (HIC). Only NaPEPPA attained the initiation efficiencies close to unity at the early stage of propagation. The homopolymerization with [HIC] 0 /[NaPEPPA] 0 = 38.9/85.1/203 led to poly(n-hexyl isocyanate)s (PHICs) with predictable MWs and low dispersities (M n,theo = 5.12/10.7/24.7 kDa; M n = 5.22/11.1/27.4 kDa; Đ = 1.11/1.10/1.06). NaPEPPA was also used to initiate the living anionic copolymerization of HIC and furfuryl isocyanate (FIC). As a result, poly(furfuryl isocyanateblock-n-hexyl isocyanate) (P(FIC-b-HIC)) was afforded by the blocky monomer sequence distribution. Based on the copolymerization kinetics, a series of polyisocyanate-based multiblock copolymers, P(FIC-b-HIC) 1 /P(FIC-b-HIC) 2 /P(FIC-b-HIC) 3 /P(FIC-b-HIC) 4 (M n,theo = 5.

Poly(n-hexyl isocyanate)s (PHICs) with chiral moieties at both ends of their polymeric chains were synthesized by living anionic polymerizations. Such PHICs were synthesized using a bidirectional initiator (sodium naphthalenide (Na-Naph)) and terminated with a chiral acid chloride, (S)-2-acetoxypropionyl chloride ((S)-Ct). Na-Naph created a covalent linkage in the middle of the chains by radical–radical coupling. PHICs containing a chiral moiety at both ends adopted conformations with an opposite helical sense in comparison with those PHICs that had the same chiral moiety at only one end of their chain. By observing these structural differences, it was hypothesized that such a “helicity inversion” occurred in the PHICs due to the covalent linkage in the middle of the chain. Therefore, to prove this assumption about helicity inversion, a comparison study of the helical behaviors between the PHIC with the chiral moiety at both ends and the PHIC with the chiral moiety at only one end was performed. The synthesized PHICs were characterized using size exclusion chromatography-multiangle laser light scattering (SEC-MALLS), MALDI-TOF mass spectrometry, NMR spectrometry, and circular dichroism (CD).

Anionic polymerization of n-hexyl isocyanate (HIC) in THF at −98 °C under 10–6 Torr for the kinetic study was performed by the initiation of sodium diphenylmethane (NaDPM) in either the absence or presence of sodium tetraphenylborate (NaBPh4; [NaBPh4]0/[NaDPM]0 = 0 or 5). The common-ion effect of NaBPh4 to suppress the formation of unstable free amidate anions led to termination-free propagation by amidate ion pairs. In [HIC]0/[NaDPM]0 = 50.8/101/201, the initiation of NaDPM early reached ∼100% efficiencies during propagation, which led to the yield of poly­(n-hexyl isocyanate)­s (PHICs) with predictable molecular weights (M n,theo = 6.50/12.7/24.7 kDa; M n = 6.50/12.7/26.1 kDa) and low dispersities (Đ = 1.06/1.07/1.15). Within the conditions, the rate of propagation accorded with a first-order dependence on [NaDPM]0, indicating that the propagating amidate ion pairs are intrinsically unimeric (nonassociated). Kinetics of anionic copolymerization of HIC and allyl isocyanate (AIC) exhibited a monomer distribution toward a tapered block sequence.