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.

An operationally simple approach to preparation of ωnorbornenyl macromonomers (MMs) is reported. Reaction of exo-N-(6hydroxyhexyl)-5-norbornene-2,3-dicarboximide or exo-N-(10-hydroxydecyl)-5-norbornene-2,3-dicarboximide with α-phenyl acrylate (α-PhA) led to novel end-capping agents, NBxPhA [x is 6 (n-hexyl) or 10 (ndecyl)]. Living anionic polymerization of styrene and methyl methacrylate followed by capping with NBxPhA yielded the desired MMs, ω-norbornenyl polystyrene (NBxPS) and ω-norbornenyl poly-(methyl methacrylate) (NBxPMMA). These MMs, formed with controlled molecular weights (M n = 2−5 kDa) and low dispersity (Đ = 1.02−1.07), upon ring-opening metathesis polymerization (ROMP) resulted in P(NB-g-PS) and P(NB-g-PMMA) bottlebrush homopolymers with ∼95% and ∼75% yield, respectively, signifying efficient end-capping efficiency. The factors affecting synthesis of NBxPS and NBxPMMA and their subsequent ROMP, such as [NBxPhA]/[sec-BuLi] ratio, the length of alkyl spacer, and varying molecular weights of the macromonomers, were optimized. Well-defined bottlebrush homopolymers with low polydispersity (Đ = 1.02−1.39) were achieved at various degrees of polymerization (DP 50−600). Additionally, copolymerization of the homopolymers through sequential ROMP furnished the bottlebrush block copolymers (M n = 262−1593 kDa, Đ = 1.09−1.32) displaying photonic crystal properties.

A novel amphiphilic polyisocyanate block copolymer with hydroxyl side groups was synthesized by a combination of living anionic polymerization and thiol−ene click chemistry. First, the living anionic block copolymerization of allyl isocyanate (AIC) and n-hexyl isocyanate (HIC) produced a well-defined block copolymer (PAIC-b-PHIC) as a precursor. The subsequent free-radical-mediated thiol−ene click reaction of this polymer with 2-mercaptoethanol at room temperature quantitatively converted the allyl side groups of the PAIC domain to hydroxyl groups, finally creating PAIC(OH)-b-PHIC. The amphiphilicity of PAIC(OH)-b-PHIC led to lamellar and cylindrical phase separations in the thin films cast from different solvents (THF and toluene). The functionalities and phase separation behaviors of PAIC(OH)-b-PHIC were characterized by NMR, SEC-MALLS, and TEM analysis.

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We developed a methodology, inspired by the folding of proteins, for the precision synthesis of hairy polymer nanoparticles. High-molar mass and narrowly dispersed graft copolymers were synthesized by graft-through ring opening metathesis polymerization, to incorporate a designated number of side chains and dimerizable cinnamic acid groups. Intrachain photodimerization collapsed the backbone and arrested it into a compact globular conformation, resulting in hairy nanoparticles topologically equivalent to a core cross-linked star polymer. The single-chain collapse process translates the molecular information written on the 1D graft copolymer into the 3D globular polymer nanoparticle, like protein folding. Unprecedented control over structural parameters was achieved, including the length, number, and composition of the side chains as well as cross-linking density. Different side chains formed distinct subdomains in the sterically congested nanoparticle state and further self-assembled into micellar aggregates in a selective solvent. Both experimental observations and computational simulations indicated that preorganization of the side chains in the block sequence produces subdomains which primarily follow the backbone length scale, while random sequences showed side chain-dependent scaling. Polymer nanoparticles with discrete multiple subdomains were produced by folding of the ternary block graft copolymers. Drastic differences in the self-assembly behavior of ABC-and ACBsequenced nanoparticles indicate that the spatial organization of subdomains can be achieved by sequence control.

To achieve molecular packing of protic-functionalized helical polymers in aqueous solution, we synthesized an amphiphilic helix–coil–helix triblock copolymer (triBCP) composed of polystyrene and dihydroxyl-functionalized polyisocyanates. Poly­(3-(glycerylthio)­propyl isocyanate)-block-polystyrene-block-poly­(3-(glycerylthio)­propyl isocyanate), P3GPIC-b-PSt-b-P3GPIC, was synthesized by postpolymerization modification. The bidirectional anionic block copolymerization of styrene (St) and allyl isocyanate (AIC) yielded triBCPs, poly­(allyl isocyanate)-block-polystyrene-block-poly­(allyl isocyanate)­s (PAIC-b-PSt-b-PAICs), with well-controlled molecular weights (M n = 5.60–99.9 kDa) and narrow dispersities (Đ = 1.14–1.18). Of them, one with the lowest MW (M n = 5.60 kDa, Đ = 1.14), which was highly organic-soluble, was utilized in the thiol–ene click reaction between allyl group and 1-thioglycerol, producing P3GPIC-b-PSt-b-P3GPIC. The amphiphilic P3GPIC-b-PSt-b-P3GPIC self-aggregated to form spherical vesicles with an average hydrodynamic diameter of 170 nm in aqueous solution, demonstrating that hydrophilic–helical P3GPIC blocks well interacted with water media maintaining their intermolecular packing.