Molecular engineering tuning optoelectronic properties of thieno[3,2-b]thiophenes-based electrochromic polymers

Thieno[3,2-b]thiophene(TT)monomers end-capped with 3,4-ethylenedioxythiophene(EDOT)moieties are electropolymerized to formπ-conjugated polymers with distinct electrochromic(EC)properties.Steric and electronic factors(electron donor and acceptor substituents)in the side groups of the TT core,as well as the structure of the polymer backbone strongly affect the electrochemical and optical properties of the polymers and their electrochromic characteristics.The studied polymers show low oxidation potentials,tunable from-0.78 to+0.30 V(vs.Fc/Fc~+)and the band gaps from 1.46 to 1.92 eV and demonstrate wide variety of color palettes in polymer films in different states,finely tunable by structural variations in the polymer backbone and the side chains.EC materials of different colors in their doped/dedoped states have been developed(violet,deep blue,light blue,green,brown,purple-red,pinkish-red,orange-red,light gray,cyan and colorless transparent).High optical contrast(up to 79%),short response time(0.57-0.80 s),good cycling stability(up to 91%at 2000 cycles)and high coloration efficiency(up to 234.6 cm2C~(-1))have been demonstrated and the influence of different factors on the above parameters of EC polymers have been discussed.     

Cationic conjugated polymers for detection and inactivation of pathogens

Conjugated polymers(CPs) are referred to a kind of fluorescent polymer materials with delocalized π-conjugated backbones.For the last decades, cationic CPs(CCPs) have been widely used in biosensor, imaging and biomedical fields due to their good photophysical properties and solubility in water medium resulting from side chain modification with ionized moieties. In this mini-review, we mainly introduced the applications of CCPs in detection and inactivation of pathogen with typical examples, and also briefly discussed the relevant mechanisms. We hold the expectation that this mini-review can offer researchers a general reference and inspire them to construct new systems with high performances of pathogen detection and antimicrobial activity.     

Hybrid Copolymerization via the Combination of Proton Transfer and Ring-opening Polymerization

Phosphazene base,t-BuP2,was employed to catalyze the proton transfer polymerization(PTP)of 2-hydroxyethyl acrylate(HEA),and PTP was further combined with ring-opening polymerization(ROP)to exploit a new type of hybrid copolymerization.The studies on homopolymerization showed that t-BuP2 was a particularly efficient catalyst for the polymerization of HEA at room temperature,giving an excellent monomer conversion.Throughout the polymerization,transesterification reactions were unavoidable,which increased the randomness in the structures of the resulting polymers.The studies on copolymerization showed that t-BuP2 could simultaneously catalyze the hybrid copolymerization via the combination of PTP and ROP at 25°C.During copolymerization,HEA not only provided hydroxyl groups to initiate the ROP ofε-caprolactone(CL)but also participated in the polymerization as a monomer for PTP.The copolymer composition was approximately equal to the feed ratio,demonstrating the possibility to adjust the polymeric structure by simply changing the monomer feed ratio.This copolymerization reaction provides a simple method for synthesizing degradable functional copolymers from commercially available materials.Hence,it is important not only in polymer chemistry but also in environmental and biomedical engineering.     

VINYL POLYMERIZATION OF NORBORNENE CATALYZED BY [2-(2-BENZIMIDAZOLYL)-6-((1-ARYLIMINOETHYL)PYRIDYL)]NICKEL CHLORIDE/MAO SYSTEM

The catalytic system of[2-(2-benzimidazolyl)-6-((1-aryliminoethyl)pyridyl)]nickel chloride/MAO(methylalu- minoxane)was found to be good active for vinyl polymerization of norbornene and provided polymers with relative narrow molecular distributions.Various reaction parameters,such as the ratios of nickel precursor to MAO or monomer norbornene, and the nature of the ligands in complexes were carefully investigated to realize their effects on the catalytic activities, polymer molecular weight and molecular...     

Studies on Novel Polymer Materials Prepared through Intermacromolecular Complexation

The basic feature of polymers is their multi-order structure. Structure change at each level offers a possibility to modify polymer properties and to develop new polymer materials. Therefore, novel polymer materials can be developed by tailoring their chain structure through chemical bonding among atoms, i.e., via the traditional molecular chemistry methods, e.g., polymerization of new monomer, controlling chain length (molecular weight and molecular weight distribution) and stereoregularity, …     

One shot strategy for preparation of asymmetric molecular double-brushes: a potential building platform for diverse polymers

正Novel macromolecular architectures with well-defined compositions and structures are of particular interest and the synthesis and self-assembly of those polymers have been an important research topic in polymer science over the past several decades.Meanwhile,through the advances in polymerization techniques,numerous well-organized polymers can be designed to construct engineering materials and     

Towards precise synthesis of functional polymers by iterative electropolymerization

正The controllable synthesis of polymers and macromolecules with precise structures is one of the biggest challenges in polymer chemistry [1]. Although polymers with welldefined architectures and compositions could now be prepared by various living polymerization techniques [1], it remains elusive to produce macromolecular materials with precise controls of monomer sequences and easy purification procedures.     

THE POLYMERIZATION OF AROMATIC AND HETEROCYCLIC DINITRILES

This review is a concise survey about the works in our laboratory on the polymerization of aromatic and heterocyclic dinitriles, including the polymerization kinetics and mechanism, synthesis of heterocyclic dinitriles, the structure of polymers, and the correlation between the structures of dinitriles and polymerization rates and thermal performances of Polymers.     

SYNTHESIS AND PROPERTIES OF NEW MESOGEN-JACKETED LIQUID CRYSTALLINE POLYMERS*

Some new mesogen-jacketed liquid crystalline polymers (MJLCP) with polymer backbones, spacers, andmesogenic units of different structures were synthesized by radical polymerization. The mesomorphic behavior of thesepolymers was examined using differential scanning calorimetry (DSC) and polarizing optical microscopy (POM). Theirliquid crystallinity is influenced by the variation of polymer backbone, spacer, mesogenic unit and its terminal groups. Theresults show that 1) a more flexible polymer main-chain is more favorable to the formation of a liquid crystal phase, while 2)a flexible spacer will decrease the "Jacket Effect" and the liquid crystallinity and 3) a subtle modification of the terminalgroups on the mesogenic unit may also have a significant influence on properties of the polymers.     

Effect of surface acidity and pore size of Al-substituted plugs-containing SBA-15 and MCM-41 silicas on the polymerization of THF

We reported here the simultaneous influence of surface acidity and pore size of Al-substituted hexagonal mesoporous silicas(Al-doped plugs-containing SBA-15 and Al-doped MCM-41) on polymerization of THF.These materials were directly synthesized by introduced aluminum isopropoxide into reaction mixture including surfactant and siliceous precursor.Al-doped plugs-containing SBA-15(denotes as PAS) samples not only possess typical two-step desorption isotherms,which implied PAS materials generated plugs in their mesochannel,but also exhibit larger pore size and thicker wall than that of Al-doped MCM-41(denotes as ACM), which implied PAS would have a great advantage on catalytic reaction involving large molecular(e.g.polymer of THF) in industrial point of view.To investigate catalytic activity of PAS and ACM with moderate acidic sites the polymerization of THF in the presence of acetic anhydride was carried out.The results showed PAS exhibiting good performance on polymerization of THF.Such result could be related to the large pore size and moderate acidic sites.     

Recent Progress in Donor-Acceptor Type Conjugated Polymers for Organic Field-effect Transistors

The recent progress in the design and synthesis of high-performance donor-acceptor conjugated polymeric semiconducting materials is reviewed from the perspective of multiscale structures. The multiscale of conjugated polymers is from the primary one-dimensional polymer molecular scale to the secondary polymer-chains interaction scale, and then to the tertiary polymer aggregate scale. This review focuses on the design and synthesis of polymer molecules, proposes new classification rules, and rati...     

Spectroscopic Properties of Methyl Ketone Bridged Electrochromic Materials: a Quantum Chemical and Experimental Study

Tuning accurately the color of electrochromic materials has been considered as a crucial step to achieve successful electrochromic display. In this paper, the effect of substitution on the color of methyl ketone bridged electrochromic materials has been investigated systematically by experimental and TDDFT methods. By screening 15 functional and 11 basis sets, a statistical method based on M052 X data is developed to estimate the maximum absorption wavelengths(λ_(max)) of electrochromic materials, based on analyzing λ_(max) of 18 molecules. For methyl ketone bridged electrochromic materials, the color from yellow to green and λ_(max) from 400 to 690 nm can be adjusted by electron-withdrawing functional group on Ar2 and electron-donating functional group on Ar1. This work not only exhibits the suitable method to predict the maximum absorption wavelength and color of electrochromic materials, but also inspires and accelerates further development of electrochromic materials for future displays.     

RECENT ADVANCES IN THE PREPARATION OF MOLECULARLY IMPRINTED POLYMERS VIA CONTROLLED RADICAL POLYMERIZATION TECHNIQUES

Molecular imprinting technique is a simple and efficient method for the preparation of polymer materials （i. e., molecularly imprinted polymers, MIPs） with tailor-made recognition sites for certain target molecules. The resulting MIPs have proven to be versatile synthetic receptors due to their high specific recognition ability, favorable mechanical, thermal and chemical stability, and ease of preparation. Recent years have witnessed significant progress in the synthesis and applications of MIPs. This review focus on the recent developments and advances in the preparation of MIPs via various controlled radical polymerization techniques.     

Synthesis of heteroarm star polymers comprising poly(4-methylphenyl vinyl sulfoxide) segment by living anionic polymerization

<正>A series of 3-arm ABC and AA'B and 4-arm ABCD,AA'BC and AA′A″B heteroarm star polymers comprising one poly(4-methylphenyl vinyl sulfoxide) segment and other segments such as polystyrene,poly(α-methylstyrene), poly(4-methoxystyrene) and poly(4-trimethylsilylstyrene) were synthesized by living anionic polymerization based on diphenylethylene(DPE) chemistry.The DPE-functionalized polymers were synthesized by iterative methodology,and the objective star polymers were prepared by two distinct methodologies based on anionic polymerization using DPE-functionalized polymers.The first methodology involves an addition reaction of living anionic polymer with excess DPE-functionalized polymer and a subsequent living anionic polymerization of 4-methylphenyl vinyl sulfoxide(MePVSO) initiated from the in situ formed polymer anion with two or three polymer segments.The second methodology comprises an addition reaction of DPE-functionalized polymer with excess sec-BuLi and a following anionic polymerization of MePVSO initiated from the in situ formed polymer anion and 3-methyl-1,1-diphenylpentyl anion as well.Both approaches could afford the target heteroarm star polymers with predetermined molecular weight,narrow molecular weight distribution (M_w/M_n1.03) and desired composition,evidenced by SEC,~1H-NMR and SLS analyses.These polymers can be used as model polymers to investigate structure-property relationships in heteroarm star polymers.     

SYNTHESIS AND FREE RADICAL RING-OPENING POLYMERIZATION OF 2-METHYL-AND 2-METHYL-9-n-BUTYL-(-7-METHYLENE-1,4,6-TRIOXA-SPIRO (4, 4)NONANE)

This paper describes the synthesis and free radical ring-opening polymerization of 2-methyl-and 2-methyl-9-n-butyl (-7-methylene-1, 4, 6-trioxaspiro (4, 4) nonane). The structures of the two polymers were verified by IR, 'H and ~(13)C NMR spectra. The substituent on 9-position of 7-methylene-trioxaspiro (4, 4) nonane affects the structure of polymer and polymerization activity. The polymerization mechanism is discussed.     

PREFACE

Due to the great contribution in high polymer production, Karl Ziegler and Giulio Natta were awarded the Nobel Prize in Chemistry in 1963. The discovery of their catalysts initiated an era of producing polymers via coordination polymerization mechanism. Coordination polymerization of olefins allows precise control over the microstructures of the polymer products, and has experienced great developments during the past half century. Polyolefins produced by     

Fine-tuning of polymer photovoltaic properties by the length of alkyl side chains

This paper reports the synthesis and characteristics of a series of alkyl-substituted planar polymers. The physical properties are carefully tuned to optimize their photovoltaic performance. Depending on the length of soluble alkyl side chains which modify the structural order and orientation substantially in polymer backbones, the device performance can be improved significantly. The tuning of HOMO energy levels optimized polymers’ spectral coverage of absorption and their hole mobility, as well as miscibility with fullerene; all these efforts enhanced polymer solar cell performances. The shortcircuit current, Jsc for polymer solar cells was increased by adjusting polymer chain packing ability. It was found that films with well distributed polymer/fullerene interpenetrating network exhibit improved solar cell conversion efficiency. Enhanced efficiency up to 5.8% has been demonstrated. The results provide important insights about the roles of flexile chains in structure-property relationship for the design of new polymers to be used in high efficient solar cells.     

Hyper-crosslinked Conjugated Microporous Polymers with Increased Micropores Promotes Confining Polymerization for Electromagnetic Absorption Application

Conjugated microporous polymers have excellent skeleton structures but poor electrical conductivity limits their applications in microwave absorption. To solve this problem, a strategy of molecular expansion and confining polymerization is proposed in this work to synthesize conductive hyper-crosslinked conjugated microporous polymer. The topology of the conjugated microporous polymer is changed into a three-dimensional skeleton structure with high specific surface area by using molecular expans...     

Synthetic Two-dimensional Organic Structures

Synthetic two-dimensional(2 D) polymers have totally different topology structures compared with traditional linear or branched polymers. The peculiar 2 D structures bring superior properties. Although, from linear to 2 D polymers, the study of these new materials is still in its infancy, they already show potential applications especially in optoelectronics, membranes, energy storage and catalysis, etc. In this review, we summarize the recent progress of the 2 D materials from three respects:(1) Chemistry—different types of polymerization reactions or supramolecular assembly to construct the 2 D networks were described;(2) Preparation methods—surface science, crystal engineering approaches and solution synthesis were introduced;(3) Functionalization and some early applications.     

Side-chain engineering of high-efficiency conjugated polymer photovoltaic materials

In recent years,conjugated polymers have attracted great attention in the application as photovoltaic donor materials in polymer solar cells(PSCs).Broad absorption,lower-energy bandgap,higher hole mobility,relatively lower HOMO energy levels,and higher solubility are important for the conjugated polymer donor materials to achieve high photovoltaic performance.Side-chain engineering plays a very important role in optimizing the physicochemical properties of the conjugated polymers.In this article,we review recent progress on the side-chain engineering of conjugated polymer donor materials,including the optimization of flexible side-chains for balancing solubility and intermolecular packing(aggregation),electron-withdrawing substituents for lowering HOMO energy levels,and two-dimension(2D)-conjugated polymers with conjugated side-chains for broadening absorption and enhancing hole mobility.After the molecular structural optimization by side-chain engineering,the2D-conjugated polymers based on benzodithiophene units demonstrated the best photovoltaic performance,with powerconversion efficiency higher than 9%.