Facile synthesis of multiblock copolymers composed of poly(tetramethylene oxide) and polystyrene using living free-radical polymerization macroinitiator

A facile synthetic strategy for well-defined multiblock copolymers utilizing ‘living’ free-radical polymerization macroinitiator has been presented. Polyurethane composed of alkoxyamine initiating units and poly(tetramethylene oxide) (PTMO) segments was prepared by polyaddition of tolylene 2,4-diisocyanate terminated PTMO with an alkoxyamine-based diol. Polymerization of styrene with the polyurethane macroinitiator was carried out under nitroxide-mediated free-radical polymerization (NMRP) condition. GPC, NMR, and IR data revealed that the polymerization was accurately controlled and well-defined polystyrene chains were inserted in the main chain of macroinitiator to give the poly(tetramethylene oxide)-b-polystyrene multiblock copolymers. The synthesized multiblock copolymers were characterized by tensile test, differential scanning calorimetry, and dynamic mechanical analysis. Mechanical properties of the multiblock copolymers can be tuned by the sufficient molecular weight control of PS chains. Soft segment of PTMO and hard segment of PS were apparently compatible due to the multiblock structure of low molecular weight segments and polar urethane groups.     

Syntheses of well-defined poly(siloxane)-b-poly(styrene) and poly(norbornene)-b-poly(styrene) block copolymers using functional alkoxyamines

Functional alkoxyamines, 1-[4-(4-lithiobutoxy)phenyl]-1-(2,2,6,6-tetramethylpiperidinyl-N-oxyl)ethane (2) and 1-[4-(2-vinyloxyethoxy)phenyl]-1-(2,2,6,6-tetramethylpiperidinyl-N-oxyl)ethane (3) were prepared, and well-defined poly(hexamethylcyclotrisiloxane)-b-poly(styrene)[poly(D₃)-b-poly(St)] and poly(norbornene)-b-poly(St) [poly(NBE)-b-poly(St)] were prepared using the alkoxyamines. The first step was preparation of poly(D₃) and poly(NBE) macroinitiators, which were obtained by the ring-opening anionic polymerization of D₃ using 2 as an initiator and the ring-opening metathesis polymerization of NBE using 3 as a chain transfer. The radical polymerization of St by the poly(D₃) and poly(NBE) macroinitiators proceeded in the ‘living’ fashion to give well-defined poly(D₃)-b-poly(St) and poly(NBE)-b-poly(St) block copolymers.     

Synthesis of poly(ethylene oxide)-block-poly(methyl methacrylate)-block-polystyrene triblock copolymers by two-step atom transfer radical polymerization

The synthesis of ABC triblock copolymer poly(ethylene oxide)-block-poly(methyl methacrylate)-block-polystyrene (PEO-b-PMMA-b-PS) via atom transfer radical polymerization (ATRP) is reported. First, a PEO-Br macroinitiator was synthesized by esterification of PEO with 2-bromoisobutyryl bromide, which was subsequently used in the preparation of halo-terminated poly(ethylene oxide)-block-poly(methyl methacrylate) (PEO-b-PMMA) diblock copolymers under ATRP conditions. Then PEO-b-PMMA-b-PS triblock copolymer was synthesized by ATRP of styrene using PEO-b-PMMA as a macroinitiator. The structures and molecular characteristics of the PEO-b-PMMA-b-PS triblock copolymers were studied by FT-IR, GPC and ¹H NMR.     

Synthesis and self-assembly of polyimide/poly(dimethylsiloxane) brush triblock copolymers

A series of novel brush triblock copolymers containing ‘glassy’ fluorinated polyimide, poly((4,4′-hexafluoroisopropylidene diphthalic anhydride)-co-(2,3,5,6-tetramethyl-1,4-phenylenediamine)) (poly(6FDA-co-TMPD)), and ‘rubbery’ polydimethylsiloxane monomethacrylate (PDMS-MA) were synthesized and characterized. Well-defined difunctional poly(6FDA-co-TMPD) with α,ω-amino end-groups was initially prepared via step-growth polymerization using precise control of the diamine (TMPD) to dianhydride (6FDA) ratio. Subsequent functionalization with 2-bromoisobutyryl bromide afforded a telechelic macroinitiator suitable for atom transfer radical polymerization (ATRP). The macroinitiator and its diamino poly(6FDA-co-TMPD) precursor were characterized via gel permeation chromatography (GPC), ¹H nuclear magnetic resonance (NMR) spectroscopic analysis and matrix assisted laser desorption ionization time-of-flight (MALDI ToF) mass spectroscopy. ATRP of PDMS-MA using the macroinitiator in different molar ratios afforded a series of brush triblock copolymers with high monomer conversions (88–94%) and varying PDMS weight fractions. Self-assembly of the triblock brush copolymers in dimethylformamide (DMF) afforded nanoparticles with hydrodynamic diameters (d_H) ranging from 87 to 109 nm, as determined by dynamic light scattering (DLS) analysis. Cross-linking of the nanoparticles was achieved via hydrogen abstraction through the thermal degradation of benzoyl peroxide. Transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM) revealed that the self-assemblies and their cross-linked derivatives had spherical morphologies.     

Synthesis and characterisation of hydroxyl end-capped telechelic polymers with poly(methyl methacrylate)-block-poly(n-butyl acrylate) backbones via atom transfer radical polymerisation

Hydroxyl end-capped telechelic polymers with poly(methyl methacrylate)-block-poly(n-butyl acrylate) (PMMA-b-PBA) backbones have been prepared via atom transfer radical polymerisation (ATRP) together with a nucleophilic substitution reaction. A hydroxyl-functionalised PMMA macroinitiator (HO-PMMA-Br) was prepared via ATRP at the optimised reaction temperature (60 °C) using 2-hydroxyethyl 2-bromoisobutyrate as the initiator. The high functionality of the bromo end group in the macroinitiator was confirmed by both ¹H NMR technique and a chain-extension reaction. Electrospray ionisation mass spectrometer proved to be a valuable tool for characterising PMMAs with a bromo end group (PMMA-Br), which provided signals corresponding to the intact polymers although multiply charged polymer chains were observed. The well-defined block copolymers HO-PMMA-b-PBA-Br were obtained by the ATRP of n-butyl acrylate using HO-PMMA-Br as a macroinitiator in a one-pot reaction at 100 °C. The kinetics as well as the dependence of the M_n,SEC and PDIs of the obtained block copolymers on the conversions of n-butyl acrylate in the chain-extension reaction suggested negligible radical termination during the reaction, demonstrating that the well-defined HO-PMMA-b-PBA-Br with a high functionality of bromo end group were obtained. The nucleophilic substitution reaction of a monohydroxyl-functionalised block copolymer HO-PMMA-b-PBA-Br with 5-amino-1-pentanol in dimethyl sulfoxide at room temperature was verified with ¹H and ¹³C NMR techniques, which resulted in a series of telechelic polymers HO-PMMA-b-PBA-OH with a functionality of hydroxyl groups up to 1.7 according to the gradient polymer elution chromatography.     

pH- and temperature-sensitive multiblock copolymer hydrogels composed of poly(ethylene glycol) and poly(amino urethane)

A series of novel pH- and temperature-responsive multiblock copolymers (poly(PEG/HEP urethane)) consisting of poly(ethylene glycol) (PEG) and poly(amino urethane) (PAU) were synthesized, and their physicochemical properties were studied. The amphiphilic block copolymers were synthesized from PEG, 1,4-bis(hydroxyethyl) piperazine (HEP) and 1,6-diisocyanato hexamethylene (HDI) in the presence of dibutyltin dilaurate as a catalyst. The resulting polymers were examined by FT-IR, ¹H and ¹³C NMR spectroscopies and gel permeation chromatography (GPC). The solution properties of the copolymers were studied by turbidity measurement and fluorescence spectroscopy. The copolymers showed a pH-dependent soluble-insoluble transition in diluted aqueous solutions. The concentrated polymer solutions exhibited a thermo-induced sol-gel-sol phase transition at pH 6.8-7.4. The gel window covers the physiological conditions. After a subcutaneous injection of the multiblock copolymer solution into mice, a transparent and soft gel was formed immediately. The in vitro release of a model anticancer drug, chlorambucil, persisted over 2 weeks under physiological conditions.     

In situ gelling aqueous solutions of pH- and temperature-sensitive poly(ester amino urethane)s

A series of novel pH- and temperature-sensitive multiblock poly(ester amino urethane)s were synthesized. The copolymers were characterized by ¹H NMR, FT-IR and GPC. In the multiblock copolymers, the tertiary amino groups of the poly(amino urethane) segments act as pH-responsive moieties, while the PCL-PEG-PCL blocks act as biodegradable and temperature-sensitive segments. At a relatively high pH (7.0 or above), the multiblock copolymer aqueous solution showed a sol-to-gel-to-aggregation transition with increasing temperature. In contrast, at a lower pH (below 7.0), the polymer solution always existed as a sol state within the experimental temperature range. The gel window covers the physiological conditions. After subcutaneous injection of the 20 wt% multiblock copolymer solutions into mice, polymeric hydrogels were formed in situ in a short time. The in vitro release of an anticancer drug, paclitaxel, persisted over 1 month under physiological conditions.     

Synthesis of amphiphilic rod-coil ABC triblock copolymers with oligo(para-phenyleneethynylene) as the middle rigid block

An amphiphilic rod-coil ABC triblock copolymers using rigid oligo(para-phenyleneethynylene) (OPE) as the middle rod segment, poly(ethylene oxide)-block-oligo(para-phenyleneethynylene)-block-polystyrene (PEO-b-OPE-b-PS), was designed and successfully synthesized. In the synthetic route, a kind of macroinitiator, PEO-b-OPE-Br was achieved by stepwise coupling of iodo-terminated poly(ethylene oxide) and oligo(para-phenyleneethynylene) with amino end group, capping with 2-bromopropionyl bromide. Subsequently, from this macroinitiator atom transfer radical polymerization (ATRP) of styrene was performed to obtain PEO-b-OPE-b-PS. The resulting copolymers were characterized by nuclear magnetic resonance (NMR) and gel permeation chromatography (GPC). All these novel copolymers were affirmed to have well-defined structures and narrow molecular weight distributions.     

New azo-chromophore-containing multiblock poly(butadiene)s synthesized by the combination of ring-opening metathesis polymerization and click chemistry

A combination of ring-opening metathesis polymerization (ROMP) and click chemistry approach was utilized for the first time in preparation of multiblock copolymers. The dibromo-functionalized telechelic poly(butadiene) (PBD) was synthesized firstly by ROMP of 1,5-cyclooctadiene in the presence of a symmetrical difunctional chain transfer agent and transformed into diazido-telechelic PBD, which was then reacted with a dialkynyl-containing azobenzene chromophore via click reaction, producing novel multiblock PBDs collected by azobenzene groups and newly formed triazole moieties. The monomer and polymer were characterized by IR, UV-vis, LC/MS, and NMR techniques. The produced multiblock copolymers have molecular weights within 13.3 and 57.8 kDa, and their polydispersity indices ranging from 1.98 to 2.38 by gel permeation chromatography measurement. The multiblock PBDs containing azo chromophores and triazole moieties with or without hydrogen-bonding interreaction with 4,4′-dihydroxybiphenyl molecule exhibited different photoisomerization efficiency from trans to cis as observation in UV-vis spectroscopy. The morphologies of multiblock PBDs were also investigated by atom force microscopy.     

Synthesis and characterization of poly(oxyethylene)–poly(caprolactone) multiblock copolymers

Novel poly(oxyethylene)/poly(caprolactone) POE/PCL copolymers were synthesized by step growth polymerization of poly(ε-caprolactone) diols and poly(ethylene glycol) diacids using dicyclohexylcarbodiimide as coupling agent. The reaction was performed at room temperature and yielded multiblock copolymers with predetermined POE and PCL block lengths. The resulting copolymers were characterized by various analytical techniques including SEC, IR, ¹H NMR, DSC and X-ray diffractometry. Data showed that the properties of these polymers can be modulated by adjusting the chain lengths of the macromonomers. In particular, one or two crystalline structures can exist within the copolymers of various crystallinities. © 1998 SCI.     

Synthesis of diblock copolymer poly(10-hydroxydecanoic acid)/polystyrene by combining enzymatic condensation polymerization and ATRP

Summary The diblock copolymers poly(10-hydroxydecanoic acid)-block-polystyrene (PHDA-b-PSt) were synthesized by combining enzymatic condensation polymerization of 10-hydroxydecanoic acid (HDA) and atom transfer radical polymerization (ATRP) of styrene (St). PHDA was firstly obtained via enzymatic condensation polymerization catalyzed by Novozyme-435. Subsequently one end of poly(10-hydroxydecanoic acid) (PHDA) chains was modified by reaction with α-bromopropionyl bromide and the other was protected by chlorotrimethylsilane (TMSCL), respectively, the resulting monofunctional macroinitiator was used in the ATRP of St using CuCl/2,2^′-bipyridine (bpy) as the catalyst system to afford the diblock copolymers including biodegradable PHDA blocks and well-defined PSt blocks.     

Synthesis of densely grafted copolymers by nitroxide-mediated radical polymerization of styrene using poly(phenylacetylene)s as a macroinitiator

Poly(phenylacetylene)s carrying alkoxyamine moieties in the side chain were prepared by Rh-catalyzed homopolymerization of 1-(4-ethynylphenyl)-1-(2,2,6,6-tetramethyl-1-piperidinyloxyl)ethane (1) and random copolymerization of 1 and 4-methoxy-1-ethynylbenzene (2a) or 4-decyloxy-1-ethynylbenzene (2b). ¹H NMR spectra showed that the poly(phenylacetylene)s adopted a cis-transoid structure. Using the poly(phenylacetylene)s as the macroinitiator the nitroxide-mediated radical polymerization of styrene (St) was carried out at 120 °C to yield densely grafted copolymers as a light yellow powder. The side chain lengths of the graft copolymers were determined by both ¹H NMR and conversion of St, which agreed with each other. The SEC profiles of the graft copolymers were unimodal at low conversions but were not unimodal at high conversion: a shoulder was observed in the high molecular=weight region and a small peak was observed in the low molecular=weight region. ¹H NMR measurements of the graft copolymers indicated that the copolymers adopted a trans-transoid structure, revealing that isomerization from cis-transoid to trans-transoid forms took place during the polymerization of St at 120 °C.     

Effect of atom transfer radical polymerization macroinitiator on properties of poly(meth)acrylate-based pentablock type of thermoplastic elastomers

We report well controlled synthesis of novel tri-component [polyisobutylene (PIB), poly(n-butyl acrylate) (PnBA) and poly(methyl methacrylate) (PMMA)] pentablock copolymers (PMMA-b-PnBA-b-PIB-b-PnBA-b-PMMA) by Atom Transfer Radical Polymerization (ATRP) using PIB as a macroinitiator. The surface properties (hydrophobicity, in vitro oxidative stability and cellular interaction) and the bulk properties (phase separation and mechanical properties) of the PIB-containing pentablock copolymers were compared with PMMA-b-PnBA-b-PDMS-b-PnBA-b-PMMA (where PDMS = polydimethylsiloxane) and conventional PMMA-b-PnBA-b-PMMA copolymers synthesized by PDMS and PnBA macroinitiators respectively. It is revealed that type of ATRP macroinitiator (with low glass transition temperature) influences the properties of resultant pentablock copolymers in terms of phase separation, mechanical properties in vitro oxidative stability, cytocompatibility and cell proliferation. Pentablock copolymers synthesized by PIB macroinitiator exhibited superior overall properties compared to pentablock copolymers synthesized by PDMS macroinitiator and neat triblock copolymer synthesized by PnBA macroinitiator. Among the copolymers tested, one with composition PIB:PnBA:PMMA = 10:64:26 (w/w) exhibited best mechanical property, oxidative stability and cytocompatibility. The newly designed PIB-containing pentablock copolymer may be useful where softness, flexibility, processability and biostability/cytocompatibility are desired.     

Aggregation of biodegradable amphiphilic poly(succinimide-co-N-propyl aspartamide) and poly(N-dodecyl aspartamide-co-N-propyl aspartamide) in aqueous medium and its preliminary drug-released properties

Two series of biodegradable amphiphilic copolymers, poly(succinimide-co-N-propyl aspartamide) (PSI-PA) and poly(N-dodecyl aspartamide-co-N-propyl aspartamide) (PDDA-PA) were synthesized by partial and total aminolysis of polysuccinimide (PSI), respectively. PSI-PA copolymers could self-aggregate in water directly under ultrasonication at room temperature. Differing from PSI-PA copolymers, the aggregates of PDDA-PA need to add PDDA-PA DMF solution into an excessive amount of water. The aggregative properties of PSI-PA and PDDA-PA copolymers have been investigated by dynamic light scattering (DLS) and surface tension measurements. Hydrophilicity of these two copolymers was attributed to the N-propyl aspartamide segments. Due to the stiff structure, succinimide segments preferred to form irregular hydrophobic microdomains, and some aggregates of PSI-PA are bimodal size distribution in water medium, while the more flexible PDDA-PA copolymer chains preferred to form monodispersed spherical aggregates. Elevated temperature could reduce the aggregate size of both PSI-PA and PDDA-PA copolymers due to the breaking of the hydrogen bonding and the releasing of the bonded water molecules. PSI-PA copolymers were surface active, while the surface tension of PDDA-PA copolymers was independent on concentration. The drug-loaded aggregates of PSI-PA also have been prepared and the preliminary release properties have been studied in vitro.     

Graft copolymerization of methylmethacrylate with N‐substituted maleimide‐styrene copolymer by ATRP

Atom transfer radical polymerization (ATRP) was employed to prepare graft copolymers having poly(MBr)‐alt‐poly(St) copolymer as backbone and poly(methyl methacrylate) (PMMA) as branches to obtain heat resistant graft copolymers. The macroinitiator was prepared by copolymerization of bromine functionalized maleimide (MBr) with styrene (St). The polymerization of MMA was initiated by poly(MBr)‐alt‐poly(St) carrying bromine groups as macroinitiator in the presence of copper bromide (CuBr) and bipyridine (bpy) at 110°C. Both macroinitiator and graft copolymers were characterized by ¹H NMR, GPC, DSC, and TGA. The ATRP graft copolymerization was supported by an increase in the molecular weight (MW) of the graft copolymers as compared to that of the macroinitiator and also by their monomodal MW distribution. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006     

A biodegradable triblock copolymer poly(ethylene glycol)-b-poly(l-lactide)-b-poly(l-lysine): Synthesis,self-assembly,and RGD peptide modification

A novel biodegradable triblock copolymer poly(ethylene glycol)-b-poly(l-lactide)-b-poly(l-lysine) (PEG–PLA–PLL) was synthesized by acidolysis of poly(ethylene glycol)-b-poly(l-lactide)-b-poly(ɛ-benzyloxycarbonyl-l-lysine) (PEG–PLA–PZLL) obtained by the ring-opening polymerization (ROP) of ɛ-benzyloxycarbonyl-l-lysine N-carboxyanhydride (ZLys NCA) with amino-terminated PEG–PLA–NH₂ as a macroinitiator, and the pendant amino groups of the lysine residues were modified with a peptide known to modulate cellular functions, Gly-Arg-Gly-Asp-Ser-Tyr (GRGDSY, abbreviated as RGD) in the presence of 1,1′-carbonyldiimidazole (CDI). The structures of PEG–PLA–PLL/RGD and its precursors were confirmed by ¹H NMR, FT-IR, amino acid analysis and XPS analysis. The cell adhesion and cell spread on the PEG–PLA–PLL/RGD film were enhanced compared to those on pure PLA film. Therefore, the novel RGD-grafted triblock copolymer is promising for cell or tissue engineering applications. Both copolymers PEG–PLA–PZLL and PEG–PLA–PLL showed an amphiphilic nature and could self-assemble into micelles of homogeneous spherical morphology. The micelles were determined by fluorescence technique, dynamic light scattering (DLS), and field emission scanning electron microscopy (ESEM) and could be expected to find application in drug and gene delivery systems.     

Synthesis and characterization of diblock,triblock, and multiblock copolymers containing poly(3‐hydroxy butyrate) units

A poly[(R,S)‐3‐hydroxybutyrate] macroinitiator (PHB‐MI) was obtained through the condensation reaction of poly[(R,S)‐3‐hydroxybutyrate] (PHB) oligomers containing dihydroxyl end functionalities with 4,4′‐azobis(4‐cyanopentanoyl chloride). The PHB‐MI obtained in this way had hydroxyl groups at two end of the polymer chain and an internal azo group. The synthesis of ABA‐type PHB‐b‐PMMA block copolymers [where A is poly(methyl methacrylate) (PMMA) and B is PHB] via PHB‐MI was accomplished in two steps. First, multiblock active copolymers with azo groups (PMMA‐PHB‐MI) were prepared through the redox free‐radical polymerization of methyl methacrylate (MMA) with a PHB‐MI/Ce(IV) redox system in aqueous nitric acid at 40°C. Second, PMMA‐PHB‐MI was used in the thermal polymerization of MMA at 60°C to obtain PHB‐b‐PMMA. When styrene (S) was used instead of MMA in the second step, ABCBA‐type PMMA‐b‐PHB‐b‐PS multiblock copolymers [where C is polystyrene (PS)] were obtained. In addition, the direct thermal polymerization of the monomers (MMA or S) via PHB‐MI provided AB‐type diblocks copolymers with MMA and BCB‐type triblock copolymers with S. The macroinitiators and block copolymers were characterized with ultraviolet–visible spectroscopy, nuclear magnetic resonance spectroscopy, gel permeation chromatography, cryoscopic measurements, and thermogravimetric analysis. The increases in the intrinsic viscosity and fractional precipitation confirmed that a block copolymer had been obtained. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1789–1796, 2004     

The influence of hydrophobic substitution on self-association of poly(ethylene oxide)-b-poly(n-alkyl glycidyl carbamate)s-b-poly(ethylene oxide) triblock copolymers in aqueous media

A series of amphiphilic poly(ethylene oxide)-b-poly(n-alkyl glycidyl carbamate)s-b-poly(ethylene oxide) triblock copolymers were synthesized by reaction between poly(ethylene oxide)-b-polyglycidol-b-poly(ethylene oxide) precursor copolymer and four n-alkyl isocyanates: ethyl, propyl, butyl and pentyl. After dissolution in water at room temperature the copolymers spontaneously form micelles. The critical micellization concentrations were determined by UV-VIS spectroscopy. The dimensions of the micelles, the aggregation numbers, and in some cases the micellar shape were determined by dynamic and static light scattering in a relatively broad temperature range. Special attention has been paid to the influence of the number of the carbon atoms in the alkyl chains, and respectively, the relative hydrophobicity of the middle block upon the self-association process. Clouding transition was observed for all of the copolymers, the clouding point being dependent upon the length of the alkyl chain.     

Styrene/(substituted styrene) copolymerization by Ph2Zn-metallocene-MAO systems: Synthesis and characterization of poly(styrene-co-p-hydroxystyrene) copolymers

Poly(styrene-co-p-tert-butyldimethylsilyloxystyrene) copolymers, P(S/p-TBDMSOS), with contents in the substituted comonomer within the 0-50% range were prepared using combined Ph₂Zn-CpTiCl₃-MAO initiator systems and some of them were used as precursors of poly(styrene-co-p-hydroxystyrene), P(S/p-HOS), copolymers. p-tert-Butyldimethylsilyloxystyrene was synthesized from p-hydroxybenzaldehyde by protecting the hydroxyl group with tert-butyldimethylchlorosilane and converting the aldehyde group into vinyl through the Wittig reaction. The P(S/p-TBDMSOS) copolymers with contents in substituted units equal or higher than 25% were atactic and those with content higher than 5% were amorphous. P(S/p-HOS) copolymers containing up to 20% of hydroxylated units were obtained by full hydrolysis in acidic medium of the corresponding P(S/p-TBDMSOS). The hydroxylated copolystyrenes displayed crystallinity for the whole range of studied compositions and their crystalline structure was essentially similar to that of s-PS homopolymers. The influence of the substituent on the modified-MAO catalyzed copolymerization and on the thermal properties of the resulting copolymers was comparatively examined.     

Monomer sequence of partially hydrolyzed poly(4-tert-butoxystyrene) and morphology of diblock copolymers composing this polymer sequence as one block

The molecular characteristics of poly(4-tert-butoxystyrene) (O) upon hydrolysis reaction were investigated. It is known that O can be converted into poly(4-hydroxystyrene) (H) through hydrolysis reaction using strong acid. In this study, a set of poly(4-tert-butoxystyrene-co-4-hydroxystyrene)s (O/H copolymers) having various conversion rates, f_Hs, were prepared. Hydrolysis reaction is found to occur uniformly by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) where the average f_H obtained was consistent with that from ¹H NMR though a certain distribution in the number of hydrolyzed units was conceived. Monomer sequence of O/H copolymers was determined by ¹³C NMR and the changes in triad concentration were obtained by spectra subtraction method. As a result, ¹³C NMR reveals that O and H are statistically distributed. To evaluate the effect of hydrolysis on microphase-separated structure, we observed the morphology of partially hydrolyzed poly(4-tert-butylstyrene-block-4-tert-butoxystyrene) (BO) by transmission electron microscopy (TEM) and small-angle X-ray scattering (SAXS). Samples with f_H from 0.21 to 0.67 form both lamellar (major component) and cylindrical (minor component) structures reflecting both the statistical manner of hydrolysis reaction and the possible localized distribution of H sequence.