Diketopyrrolopyrrole‐based Conjugated Polymers Bearing Branched Oligo(Ethylene Glycol) Side Chains for Photovoltaic Devices

Conjugated polymers are essential for solution‐processable organic opto‐electronic devices. In contrast to the great efforts on developing new conjugated polymer backbones, research on developing side chains is rare. Herein, we report branched oligo(ethylene glycol) (OEG) as side chains of conjugated polymers. Compared with typical alkyl side chains, branched OEG side chains endowed the resulting conjugated polymers with a smaller π‐π stacking distance, higher hole mobility, smaller optical band gap, higher dielectric constant, and larger surface energy. Moreover, the conjugated polymers with branched OEG side chains exhibited outstanding photovoltaic performance in polymer solar cells. A power conversion efficiency of 5.37 % with near‐infrared photoresponse was demonstrated and the device performance could be insensitive to the active layer thickness.     

Hyperbranch‐polyethyleniminated functional polymers. I. Synthesis,characterization of novel ABA type of dumbbell‐like polyethyleniminated polyoxypropylenediamines,and their complexing properties with copper(II) ions in aqueous solution

Novel ABA‐type dumbbell‐like water‐soluble copolymers [D230(EI)₄, D400(EI)₄, and D400(EI)₈] were synthesized by introducing ethylenimine (EI) groups into both sides of polyoxypropylenediamines via a simple in situ ethylamination of polyoxypropylenediamine with 2‐chloroethylamine hydrochloride. The structures of the resultant polymers were identified by Fourier transform infrared spectroscopy and ¹H NMR. The percentages of primary, secondary, and tertiary amine present were determined by the potentiometric titration method after treatments with the appropriate chemicals of salicylaldehyde and acetic anhydride. The surface tension and solubilizing behavior of pyrene in the presence of these polymers in aqueous medium were also investigated, and the efficiency to reduce the surface tension and solubilizing behavior of pyrene depends on the attachments of EI to polymer backbone. The chelating properties of these polymers were examined quantitatively by ultraviolet–visible (UV–vis) spectroscopy in the presence of Cu²⁺ ions in aqueous solution, and continuous variation analysis revealed that the most stable complex is formed at the normality ratio of [N]/[Cu²⁺] = 3.0. UV–vis spectroscopy and transmission electron microscopy were used to evaluate the dumbbell‐like water‐soluble copolymer, D400(EI)₈, as a stabilizer for preparing colloidal noble metal nanoparticles (Au and Pt) in aqueous solution. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1360–1370, 2003     

Side‐Chain Engineering of Benzodithiophene‐Fluorinated Quinoxaline Low‐Band‐Gap Co‐polymers for High‐Performance Polymer Solar Cells

A new series of donor–acceptor co‐polymers based on benzodithiophene and quinoxaline with various side chains have been developed for polymer solar cells. The effect of the degree of branching and dimensionality of the side chains were systematically investigated on the thermal stability, optical absorption, energy levels, molecular packing, and photovoltaic performance of the resulting co‐polymers. The results indicated that the linear and 2D conjugated side chains improved the thermal stabilities and optical absorptions. The introduction of alkylthienyl side chains could efficiently lower the energy levels compared with the alkoxyl‐substituted analogues, and the branched alkoxyl side chains could deepen the HOMO levels relative to the linear alkoxyl chains. The branched alkoxyl groups induced better lamellar‐like ordering, but poorer face‐to‐face packing behavior. The 2D conjugated side chains had a negative influence on the crystalline properties of the co‐polymers. The performance of the devices indicated that the branched alkoxyl side chains improved the V_oc, but decreased the J_sc and fill factor (FF). However, the 2D conjugated side chains would increase the V_oc, J_sc, and FF simultaneously. For the first time, our work provides insight into molecular design strategies through side‐chain engineering to achieve efficient polymer solar cells by considering both the degree of branching and dimensionality.     

Synthesis and characterization of pH‐sensitive and thermosensitive double hydrophilic graft copolymers

A series of poly(N‐isopropylacrylamide)‐co‐poly(N^ε‐benzyloxycarbonyl‐L ‐lysine) graft copolymers (PNIPAm‐co‐PZLLys) with different side chains (degree of polymerization, DP = 5～40) and unit ratios (from 30 to 70 mol %) were prepared via free radical polymerization, followed by cleaving benzyloxycarbonyl groups (Z groups) to obtain the double hydrophilic graft copolymer, poly(N‐isopropylacrylamide)‐co‐poly(L ‐lysine) (PNIPAm‐co‐PLLys). The pH‐ and temperature‐response properties of the graft copolymers in aqueous solution were studied. The experimental results indicate L15‐N30 and L15N‐70, that is, the PNIPAm‐co‐PLLys having the poly(L ‐lysine) of DP = 15 as side chains as well as 30 and 70 mol %, respectively, of PNIPAm as backbone, have coil‐to‐helix transitions from pH 6 to pH 12 at room temperature and form uniform nanoscale micelle‐like dispersions in aqueous solution at pH 12. The graft copolymers also could form uniform and nanoscale micelle‐like structures at 50 °C in pH 6 buffer solution due to slightly polymer aggregation. With temperature and pH increased, both the deprotonated PLLys side chains and PNIPAm backbone become hydrophobic, leading to polymer precipitation. These results illustrate that a double tunable hydrophilic graft copolymer had been successfully synthesized via a simple radical polymerization, and could form micelles without serious polymer aggregation at a lower pH and a higher temperature. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Host–Guest Binding‐Site‐Tunable Self‐Assembly of Stimuli‐Responsive Supramolecular Polymers

Despite the remarkable progress made in controllable self‐assembly of stimuli‐responsive supramolecular polymers (SSPs), a basic issue that has not been consideration to date is the essential binding site. The noncovalent binding sites, which connect the building blocks and endow supramolecular polymers with their ability to respond to stimuli, are expected to strongly affect the self‐assembly of SSPs. Herein, the design and synthesis of a dual‐stimuli thermo‐ and photoresponsive Y‐shaped supramolecular polymer (SSP2) with two adjacent β‐cyclodextrin/azobenzene (β‐CD/Azo) binding sites, and another SSP (SSP1) with similar building blocks, but only one β‐CD/Azo binding site as a control, are described. Upon gradually increasing the polymer solution temperature or irradiating with UV light, SSP2 self‐assemblies with a higher binding‐site distribution density; exhibits a flower‐like morphology, smaller size, and more stable dynamic aggregation process; and greater controllability for drug‐release behavior than those observed with SSP1 self‐assemblies. The host–guest binding‐site‐tunable self‐assembly was attributed to the positive cooperativity generated among adjacent binding sites on the surfaces of SSP2 self‐assemblies. This work is beneficial for precisely controlling the structural parameters and controlled release function of SSP self‐assemblies.     

Temperature‐induced self‐assembly of degalactosylated xyloglucan at low concentration

Xyloglucan is a natural polysaccharide having a cellulose‐like backbone and hydroxyl groups‐rich side‐chains. In its native form the polymer is water‐soluble and forms gel only in presence of selected co‐solutes. When a given fraction of galactosyl residues are removed by enzymatic reaction, the polymer acquires the ability to form a gel in aqueous solution at physiological temperatures, a property of great interest for biomedical/pharmaceutical applications. This work presents data on the effect of a temperature increase on degalactosylated xyloglucan dispersed in water at concentration low enough not to run into macroscopic gelation. Results obtained over a wide interval of length scales show that, on increasing temperature, individual polymer chains and pre‐existing clusters self‐assemble into larger structures. The process implies a structural rearrangement over a few nanometers scale and an increase of dynamics homogeneity. The relation of these findings to coil‐globule transition and phase separation is discussed. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015 , 53, 1727–1735     

Comb‐like polymers pendanted with elastin‐like peptides showing sharp and tunable thermoresponsiveness through dynamic covalent chemistry

Comb‐like polymers carrying two elastin‐like polypeptide (ELP) pendants in each repeat unit were synthesized. The densely attached peptide chains afford these polymers with sharp thermally induced phase transitions, and their lower critical solution temperature (LCST) can be varied with molecular weights, solution pH and salt concentrations. Through amino terminals in ELP pendants, oligoethylene glycol (OEG)‐based dendrons cored with aldehyde were attached to the polymers through dynamic covalent imines. By virtue of dynamic characteristics of these novel dendronized polymers, their LCSTs can be tuned significantly by dendron coverage to shift from that dominated by ELPs to that dominated by OEG dendrons. Furthermore, dendron coverage can be enhanced obviously by the thermally induced phase transitions or greatly by freezing the polymer aqueous solutions. The work provides a convenient methodology to improve thermoresponsiveness of ELPs through polymer topology and to switch their properties through dynamic covalent chemistry. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 3379–3387     

Aqueous solution behavior of comb‐shaped poly(2‐ethyl‐2‐oxazoline)

A series of comb polymers consisting of a methacrylate backbone and poly(2‐ethyl‐2‐oxazoline) (PEtOx) side chains was synthesized by a combination of cationic ring‐opening polymerization and reversible addition–fragmentation chain transfer polymerization. Small‐angle neutron scattering (SANS) studies revealed a transition from an ellipsoidal to a cylindrical conformation in D₂O around a backbone degree of polymerization of 30. Comb‐shaped PEtOx has lowered T_g values but a similar elution behavior in liquid chromatography under critical conditions in comparison to its linear analog was observed. The lower critical solution temperature behavior of the polymers was investigated by turbidimetry, dynamic light scattering, transmission electron microscopy, and SANS revealing decreasing T_cp in aqueous solution with increasing molar mass, the presence of very few aggregated structures below T_cp, a contraction of the macromolecules at temperatures 5 °C above T_cp but no severe conformational change of the cylindrical structure. In addition, the phase diagram including cloud point and coexistence curve was developed showing an LCST of 75 °C of the binary mixture poly[oligo(2‐ethyl‐2‐oxazoline)methacrylate]/water. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013     

Side chain impacts on pH‐ and thermo‐responsiveness of tertiary amine functionalized polypeptides

The systemic investigation of the structural impacts of side chains on the pH‐ and thermo‐responsiveness of tertiary amine functionalized poly(l ‐glutamate)s (TA‐PGs) was carried out. The TA‐PGs polymers were effectively synthesized by Cu(I)‐catalyzed azide‐alkyne cycloaddition click reaction of azido tertiary amines with poly(γ‐propargyl‐l ‐glutamate) (PPLG). Turbimetric measurements were performed to characterize the pH‐ and temperature‐induced phase transition of TA‐PGs in aqueous solution, which suggested a structural dependence of the properties on the N‐substituted groups and the “linkers” between 1,2,3‐triazole ring and the tertiary amine groups in the side chains. In detail, the pH responsive properties of TA‐PGs were basically determined by the hydrophobicity of the N‐substituted groups in the side chains and the pH transition point (pH_t) decreased as the increasing hydrophobicity of the N‐substituted groups, while the temperature‐responsiveness of TA‐PGs were affected by either the N‐substituted groups or the “linkers.” TA‐PGs with a moderate N‐substituted amine group (e.g., DEA, PR, and PD) or a branched “linker” (e.g., iso‐propylene and 2‐methylpropylene group) were more likely to express the LCST‐type phase transition tuned by pH variation. These structure–property relationships revealed in this study would help to develop the applications of TA‐PGs in smart drug delivery systems. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 671–679     

Novel thermo‐responsive self‐assembly micelles from a double brush‐shaped PNIPAM‐g‐(PA‐b‐PEG‐b‐PA)‐g‐PNIPAM block copolymer with PNIPAM polymers as side chains

A novel double brush‐shaped copolymer with amphiphilic polyacrylate‐b‐poly(ethylene glycol)‐b‐poly acrylate copolymer (PA‐b‐PEG‐b‐PA) as a backbone and thermosensitive poly(N‐isopropylacrylamide) (PNIPAM) long side chains at both ends of the PEG was synthesized via an atom transfer radical polymerization (ATRP) route, and the structure was confirmed by FTIR, ¹H NMR, and SEC. The thermosensitive self‐assembly behavior was examined via UV‐vis, TEM, DLS, and surface tension measurements, etc. The self‐assembled micelles, with low critical solution temperatures (LCST) of 34–38 ^°C, form irregular fusiform and/or spherical morphologies with single, double, and petaling cores in aqueous solution at room temperature, while above the LCST the micelles took on more regular and smooth spherical shapes with diameter ranges from 45 to 100 nm. The micelle exhibits high stabilities even in simulated physiological media, with low critical micellization concentration (CMC) up to 5.50, 4.89, and 5.05 mg L^?1 in aqueous solution, pH 1.4 and 7.4 PBS solutions, respectively. The TEM and DLS determination reveled that the copolymer micelle had broad size distribution below its LCST while it produces narrow and homogeneous size above the LCST. The cytotoxicity was investigated by MTT assays to elucidate the application potential of the as‐prepared block polymer brushes as drug controlled release vehicles. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Water‐soluble conjugated polymers: Synthesis and optical properties

Two sets of water‐soluble poly(phenylene vinylene)s were synthesized and their optical properties were studied. The aqueous solubility of all these polymers is rendered by pendant sulfonate groups. One set of polymers (polymer I series) contains, in addition to the sulfonate pendants, dimethoxy substituents, while the other (polymer II series) contains oligo(ethylene oxide) side chains. Within each set, polymers containing lithium (Ia and IIa), sodium (Ib and IIb), and potassium (Ic and IIc) counter ions were prepared. The two sets of polymers showed different properties from physical appearance (fiber vs film) to thermal properties and to optical properties. It was found that set I polymers, with shorter side chains, exhibit stronger aggregation in aqueous solutions than set II polymers, which led to their lower fluorescence quantum yields and lower polymer‐to‐MV²⁺ quenching efficiencies. Within each set, the effect of counter ions on optical properties was noted. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5123–5135, 2007     

Polyglycidol Based Amphiphilic Double‐Comb Copolymers and Their Self‐Association in Aqueous Solution

Herein, we report synthesis and self‐association properties of amphiphilic double‐comb polymers with polyglycidol backbones. First, a bifunctional polyglycidol precursor is synthesized via monomer activated anionic polymerization. Next, two efficient and orthogonal polymer analogous reactions are carried out for grafting hydrophilic oligoethylene glycol side chains and hydrophobic linear aliphatic side‐chains. The polymers are analyzed by means of NMR, GPC, and DSC. From the DSC analysis of the bulk samples it is evident that aliphatic side chains segregate from the polar backbone and thus crystallize. Furthermore, in aqueous media the double‐comb polymers spontaneously self‐assemble to form a multilayer structure. The present results pave a way to tailor and design amphiphilic polymers based on glycidols. Major advantages are spontaneous self‐assembly in water and the possibility to form onion polymersomes relevant to encapsulation.

     

Bio‐based comb‐like copolymers derived from alkyl 10‐undecenoates and maleic anhydride

In this article, 10‐undecenoic acid, based on castor oil, was used a raw material for the synthesis of alternating copolymers. ω‐Unsaturated fatty esters as alkyl 10‐undecenoates were prepared by the esterification reaction of 10‐undecenoic acid with alkyl alcohol. A series of comb‐like copolymers were synthesized by free radical polymerization from maleic anhydride and alkyl 10‐undecenoates copolymers with different length of alkyl side chains in a toluene solution. These copolymers were investigated by ¹H and ¹³C nuclear magnetic resonance, Fourier transform infrared spectroscopy, gel permeation chromatography, thermogravimetric analysis, differential scanning calorimetry (DSC). The copolymers were obtained in a low molecular weight in a range 3370–12,240 g mol⁻¹ and their structural characterization indicated the formation of alternating copolymers. DSC characterization revealed that these comb‐like copolymers showed amorphous to semicrystalline behavior by increasing the length of side chains. The bio‐based comb‐like copolymers allow for the development of new polymeric materials for several applications. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 1039–1045     

Synthesis of dendronized polymer brushes containing metallo‐supramolecular polymer side chains

A new kind of dendronized polymer brush with metallo‐supramolecular polymer side chains was fabricated by a combination of macromonomer and graft‐to approach. The alternating copolymers of maleic anhydride and styryl macromonomers pendant with Fréchet‐type dendrons of three generations were reported previously. In this article, terpyridine groups were introduced along the backbone of the dendronized polymers through the amidolysis of anhydride groups. The terpyridine functionalized PEO linear chains were then incorporated through the complexation of terpyridine and Ru(II) ion. Thus, dendronized polymer brushes with amphiphilic properties were synthesized. AFM analysis showed worm‐like single molecular morphologies of the polymers of three generations, and ¹H NMR analysis indicated that such molecular brushes had an amphiphilic nature in solution. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 3303–3310, 2007     

Criss‐cross amphiphilic polymers and analogous model systems

A new class of amphiphilic polymers carrying two pendant docosyl (C22) chains, located at periodic intervals that are separated by PEG chains of varying lengths, was synthesized via a simple melt‐transesterification polymerization, using dimethyl, 2,5‐didocosyloxyterephthalate as one of the monomers. DSC, variable temperature FT‐IR, and WAXS studies demonstrated that immiscibility between the pendant docosyl units and the backbone PEG segments drives their self‐segregation; this results in the crystallization of the pendant docosyl segments and the generation of a lamellar morphology with the alkyl segments and the PEG chains occupying alternate layers. Based on the study of model criss‐cross amphiphiles that resemble the polymer repeat unit, it is postulated that the chains reconfigure such that both the docosyl chains fold to one side of the terephthalate unit while the PEG segments form a loop on the other side; these chains then organize in a bilayer to form the lamellar structure. The simplicity of the synthesis and the rather unique properties of these polymers suggests that such a design could be translated to develop other interesting functional materials that could exploit the immiscibility‐driven microphase separation for the generation of sub‐10 nm domains; these could have potential applications, such as in membranes, solid polymer electrolyte formulations, and so forth. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 1554–1563     

On the “Tertiary Structure” of Poly‐Carbenes; Self‐Assembly of sp3‐Carbon‐Based Polymers into Liquid‐Crystalline Aggregates

The self‐assembly of poly(ethylidene acetate) (st‐PEA) into van der Waals‐stabilized liquid‐crystalline (LC) aggregates is reported. The LC behavior of these materials is unexpected, and unusual for flexible sp³‐carbon backbone polymers. Although the dense packing of polar ester functionalities along the carbon backbone of st‐PEA could perhaps be expected to lead directly to rigid‐rod behavior, molecular modeling reveals that individual st‐PEA chains are actually highly flexible and should not reveal rigid‐rod induced LC behavior. Nonetheless, st‐PEA clearly reveals LC behavior, both in solution and in the melt over a broad elevated temperature range. A combined set of experimental measurements, supported by MM/MD studies, suggests that the observed LC behavior is due to self‐aggregation of st‐PEA into higher‐order aggregates. According to MM/MD modeling st‐PEA single helices adopt a flexible helical structure with a preferred trans‐gauche syn‐syn‐anti‐anti orientation. Unexpectedly, similar modeling experiments suggest that three of these helices can self‐assemble into triple‐helical aggregates. Higher‐order assemblies were not observed in the MM/MD simulations, suggesting that the triple helix is the most stable aggregate configuration. DLS data confirmed the aggregation of st‐PEA into higher‐order structures, and suggest the formation of rod‐like particles. The dimensions derived from these light‐scattering experiments correspond with st‐PEA triple‐helix formation. Langmuir–Blodgett surface pressure–area isotherms also point to the formation of rod‐like st‐PEA aggregates with similar dimensions as st‐PEA triple helixes. Upon increasing the st‐PEA concentration, the viscosity of the polymer solution increases strongly, and at concentrations above 20 wt % st‐PEA forms an organogel. STM on this gel reveals the formation of helical aggregates on the graphite surface–solution interface with shapes and dimensions matching st‐PEA triple helices, in good agreement with the structures proposed by molecular modeling. X‐ray diffraction, WAXS, SAXS and solid state NMR spectroscopy studies suggest that st‐PEA triple helices are also present in the solid state, up to temperatures well above the melting point of st‐PEA. Formation of higher‐order aggregates explains the observed LC behavior of st‐PEA, emphasizing the importance of the “tertiary structure” of synthetic polymers on their material properties.     

Synthesis of well‐defined side chain fullerene polymers and study of their self‐aggregation behaviors

Monoalkynyl‐functionalized fullerene was precisely synthesized starting with pristine fullerene (C₆₀) and characterized by multiple techniques. Methyl methacrylate and 6‐azido hexyl methacrylate were then randomly copolymerized via reversible addition fragmentation chain transfer polymerization to build polymer backbones with well‐controlled molecular weights and copolymer compositions. Finally, these two moieties were covalently assembled into a series of well‐defined side chain fullerene polymers (SFPs) via the copper‐mediated click reaction which was verified by Fourier transform infrared spectroscopy and ¹H NMR. The fullerene loadings of the resultant polymers were estimated by thermogravimetric analysis and UV–vis spectroscopy, demonstrating consistent and high conversions in most of the samples. The morphology studies of the SFPs were performed both in solution and on solid substrates. Very intriguing self‐aggregation behaviors were detected by both gel permeation chromatography and dynamic light scattering analyses. Furthermore, the scanning electron microscopic images of these polymers showed the formation of various supramolecular nanoparticle assemblies and crystalline‐like clusters depending on the fullerene contents and polymer chain lengths. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 3572–3582     

Association of hydrophobically α,ω‐end‐capped poly(2‐methyl‐2‐oxazoline) in water

The α,ω‐end‐capped poly(2‐methyl‐2‐oxazoline) (C_n‐POXZ‐C_n) have been synthesized by a one‐pot process using cationic ring‐opening polymerization with an appropriate initiator and terminating agent. The polymers bearing different alkyl groups C₁₂ and C₁₈ have molecular weight in the range of 2.4 × 10³ to 14 × 10³ with a small polydispersity index. The solution behavior of the free chains has been analyzed in a nonselective solvent, dichloromethane, by small‐angle neutron scattering and dynamic light scattering. These amphiphilic polymers associate in water to form flower‐like micellar structures. Critical micelle concentrations, investigated by fluorescence technique, are in the range of 0.03–0.5 g L^?1 and are dependent on the hydrophilic/lipophilic balance. The structural properties of the aggregates have also been investigated by viscometry. Intrinsic viscosities of these polymers are in the same range as that of the precursors poly(2‐methyl‐2‐oxazoline) (POXZ) and mono‐functionalized polymers. Large viscosity increase corresponding to intermicellar bridging was observed in the vicinity of the micelle overlap concentration. Addition of hydroxypropyl β‐cyclodextrin (HβCD) has dissociated the aggregates and the intrinsic viscosities of the HβCD‐end‐capped chains have become comparable with the ones of POXZ precursor chains. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2477–2485, 2010     

Well‐controlled ATRP of 2‐(2‐(2‐azidoethyoxy)ethoxy)ethyl methacrylate for high‐density click functionalization of polymers and metallic substrates

The combination of atom transfer radical polymerization (ATRP) and click chemistry has created unprecedented opportunities for controlled syntheses of functional polymers. ATRP of azido‐bearing methacrylate monomers (e.g., 2‐(2‐(2‐azidoethyoxy)ethoxy)ethyl methacrylate, AzTEGMA), however, proceeded with poor control at commonly adopted temperature of 50 °C, resulting in significant side reactions. By lowering reaction temperature and monomer concentrations, well‐defined pAzTEGMA with significantly reduced polydispersity were prepared within a reasonable timeframe. Upon subsequent functionalization of the side chains of pAzTEGMA via Cu(I)‐catalyzed azide‐alkyne cycloaddition (CuAAC) click chemistry, functional polymers with number‐average molecular weights (M_n) up to 22 kDa with narrow polydispersity (PDI < 1.30) were obtained. Applying the optimized polymerization condition, we also grafted pAzTEGMA brushes from Ti6Al4 substrates by surface‐initiated ATRP (SI‐ATRP), and effectively functionalized the azide‐terminated side chains with hydrophobic and hydrophilic alkynes by CuAAC. The well‐controlled ATRP of azido‐bearing methacrylates and subsequent facile high‐density functionalization of the side chains of the polymethacrylates via CuAAC offers a useful tool for engineering functional polymers or surfaces for diverse applications. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 1268–1277     

Synthesis and properties of comb polymers with semirigid mesogen‐jacketed polymers as side chains

A series of novel comb polymers, poly{2,5‐bis[(4‐methoxyphenyl)oxycarbonyl]styrene}‐g‐polystyrene (PMPCS‐g‐PS), with mesogen‐jacketed rigid side chains were synthesized by the “grafting onto” method from α‐yne‐terminated PMPCS (side chain) and poly(vinylbenzyl azide) (backbone) by Cu(I)‐catalyzed 1,3‐dipolar cycloaddition click reaction. The α‐yne‐terminated PMPCS was synthesized by Cu(I)‐catalyzed atom transfer radical polymerization initiated by a yne‐functional initiator. Poly(vinylbenzyl azide) was prepared by polymerizing vinylbenzyl chloride using nitroxide mediated radical polymerization to obtain poly(vinylbenzyl chloride) as the precursor which was then converted to the azide derivative. The chemical structure and architectures of PMPCS comb polymers were confirmed by ¹H NMR, gel permeation chromatography, and multiangle laser light scattering. Both surface morphologies and solution behaviors were investigated. Surface morphologies of PMPCS combs on different surfaces were investigated by scanning probe microscopy. PMPCS combs showed different aggregation morphologies when depositing on silicon wafers with/without chemical modification. The PMPCS comb polymers transferred to polymer‐modified silicon wafers using the Langmuir‐Blodgett technique showed a worm‐like chain conformation. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012