Water soluble azido polyisocyanopeptides as functional β‐sheet mimics

The design and synthesis of functional biomimetic water soluble polymers with a defined secondary structure has been developed using β‐sheet polyisocyanopeptide scaffolds. Water soluble isocyanopolymers were prepared by random copolymerisation of the azido functionalized isocyanopeptides with nonfunctionalised methyl ester isocyanides derived from alanine. Upon saponification of the latter function a rigid rod water soluble polymer was obtained with an accessible azide for postfunctionalization. The potential of these biomimetic polymers was successfully demonstrated by using the click chemistry reaction of these polymers with an acetylene functionalised rhodamine dye. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 4150–4164, 2009     

Thermomechanical enhancement of DPP-4T through purposeful π-conjugation disruption

The design of polymer-based organic semiconductors that offer mechanical deformability while maintaining efficient semiconducting characteristics remains a significant challenge. Recent synthetic efforts have incorporated small alkyl segments directly into otherwise π-conjugated polymer backbones to enhance processability, mechanical deformability, and other properties. The resulting polymers can be used as stand-alone materials or as matrix polymers in complementary semiconducting polymer blends offering reasonable charge-carrier transport properties, thermal healing, and deformability. Here, a family of diketopyrrolopyrrole-tetrathiophene variants is explored via large-scale atomistic molecular dynamics simulations to examine the effect of alkyl segments incorporated into the polymer backbone on the polymer structure, dynamics, and thermal properties. Longer alkyl segments lead to polymer chains that are more flexible, compact, and mobile, with lower glass transition temperatures for the condensed phase.     

聚合物在受限层空间中的形态结构演变及相关性能研究进展

自然界中的层状有序结构如强韧的贝壳、树木等,往往带来优异的性能或特殊的功能。作为仿生材料学在高分子加工成型技术中的应用,聚合物微纳层共挤出技术是通过特殊的流道设计对聚合物熔体进行多次强制分割叠加,来制备高性能交替多层聚合物材料的新方法。层倍增器单元对熔体的多重力场作用,为多相多组分体系形态的原位调控提供了可能。而通过两相交替层状排布形成的受限层空间和丰富的层界面不仅赋予了材料独特的力学、光电、阻隔等性能,还为聚合物结晶调控提供了理想的研究模型。本文简要综述了近年来在层倍增过程中聚合物的形态结构演变及其对相关性能影响方面的研究进展。     

仿生高分子的研究进展

本文介绍了近年来结构仿生高分子材料和功能仿生高分子材料方面的研究进展,介绍了生物材料的多级有序结构、智能水凝胶、仿荷叶表面、高分子在细胞培养和生物矿化等方面的研究结果,探讨了这一领域的可能发展方向.     

Synthesis and single-molecule studies of a well-defined biomimetic modular multidomain polymer using a peptidomimetic beta-sheet module

In the pursuit of advanced biomaterials with combined strength, toughness, and elasticity, a new class of well-defined modular polymers has been synthesized, and their nanomechanical properties have been studied using atomic force microscopy. These polymers are based on a peptidomimetic beta-sheet-based double-closed loop (DCL) module, which was designed to overcome the limitation of the modular polymers we reported previously (J. Am. Chem. Soc. 2004, 126, 2059). Single-molecule force-extension experiments revealed the sequential unfolding of these modules as the polymer is stretched, resulting in more regular sawtooth-patterned curves similar to those seen in titin and other biopolymers. The single-molecule data agreed well with computer modeling, which suggested that hydrogen bonding and pi-stacking are both involved in the formation of small DCL clusters along the polymer chain.     

Physical organic chemistry of supramolecular polymers

Unlike the case of traditional covalent polymers, the entanglements that determine properties of supramolecular polymers are defined by very specific, intermolecular interactions. Recent work using modular molecular platforms to probe the mechanisms underlying mechanical response of supramolecular polymers is reviewed. The contributions of supramolecular kinetics, thermodynamics, and conformational flexibility to supramolecular polymer properties in solutions of discrete polymers, in networks, and at interfaces, are described. Molecule-to-material relationships are established through methods reminiscent of classic physical organic chemistry.     

Light-Driven Continual Oscillatory Rocking of a Polymer Film

Achieving oscillatory motion in polymers without requiring on/off switching of stimuli is a current challenge. Hereby, a free-standing liquid crystal polymer (LCP) is demonstrated to undergo a sustained oscillatory motion when triggered by light, moving back and forth, resembling the motion of a rocking-chair. Two polymer films having different azobenzene photo-switches have been studied, revealing photoswitch requirements as well as illumination conditions necessary to sustain oscillations. The motion presented here shows how feedback loops involving light-triggered actuation, self-shadowing and a shifting center of gravity can be utilized to achieve self-sustained motion in free-standing polymers.     

Polymers with Special Properties Through Ordered Structures

The material properties of polymers depend on both the structure and morphology of the bulk polymer and on the primary structure of the macromolecules. It is a challenge to specifically control the supermolecular structure of polymeric systems by the architecture of the individual macromolecule as it is realized, for example, in biopolymers.     

对功能高分子课程教学的思考

功能高分子的设计思想是功能高分子课程的灵魂 ,它以高分子物理学所研究的结构与性能之间关系为基础。结构与性能之间的关系是贯穿功能高分子课程始末的主线。功能高分子材料有三种设计途径 ,即化学结构设计、聚集态结构设计和复合结构设计     

Template-Free Self-Assembly of Two-Dimensional Polymers into Nano/Microstructured Materials

In the past few decades, enormous efforts have been made to synthesize covalent polymer nano/microstructured materials with specific morphologies, due to the relationship between their structures and functions. Up to now, the formation of most of these structures often requires either templates or preorganization in order to construct a specific structure before, and then the subsequent removal of previous templates to form a desired structure, on account of the lack of “self-error-correcting” properties of reversible interactions in polymers. The above processes are time-consuming and tedious. A template-free, self-assembled strategy as a “bottom-up” route to fabricate well-defined nano/microstructures remains a challenge. Herein, we introduce the recent progress in template-free, self-assembled nano/microstructures formed by covalent two-dimensional (2D) polymers, such as polymer capsules, polymer films, polymer tubes and polymer rings.     

Microchannel DNA sequencing matrices with switchable viscosities

We review the variety of thermo-responsive and shear-responsive polymer solutions with "switchable" viscosities that have been proposed for application as DNA sequencing matrices for capillary and microfluidic chip electrophoresis. Generally, highly entangled polymer solutions of high-molar mass polymers are necessary for the attainment of long DNA sequencing read lengths (> 500 bases) with short analysis times (< 3 h). However, these entangled polymer matrices create practical difficulties for microchannel electrophoresis with their extremely high viscosities, necessitating high-pressure loading into capillaries or chips. Shear-responsive (shear-thinning) polymer matrices exhibit a rapid drop in viscosity as the applied shear force is increased, but still require a high initial pressure to initiate flow of the solution into a microchannel. Polymer matrices designed to have thermo-responsive properties display either a lowered (thermo-thinning) or raised (thermo-thickening) viscosity as the temperature of the solution is elevated. These properties are generally designed into the polymers by the incorporation of moderately hydrophobic groups in some part of the polymer structure, which either phase-separate or hydrophobically aggregate at higher temperatures. In their low-viscosity states, these matrices that allow rapid loading of capillary or chip microchannels under low applied pressure. The primary goal of work in this area is to design polymer matrices that exhibit this responsive behavior and hence easy microchannel loading, without a reduction in DNA separation performance compared to conventional matrices. While good progress has been made, thermo-responsive matrices have yet to offer sequencing performance as good as nonthermo-responsive networks. The challenge remains to accomplish this goal through the innovative design of novel polymer structures.     

Polymer composition and substrate influences on the adhesive bonding of a biomimetic, cross-linking polymer

Hierarchical biological materials such as bone, sea shells, and marine bioadhesives are providing inspiration for the assembly of synthetic molecules into complex structures. The adhesive system of marine mussels has been the focus of much attention in recent years. Several catechol-containing polymers are being developed to mimic the cross-linking of proteins containing 3,4-dihydroxyphenylalanine (DOPA) used by shellfish for sticking to rocks. Many of these biomimetic polymer systems have been shown to form surface coatings or hydrogels; however, bulk adhesion is demonstrated less often. Developing adhesives requires addressing design issues including finding a good balance between cohesive and adhesive bonding interactions. Despite the growing number of mussel-mimicking polymers, there has been little effort to generate structure-property relations and gain insights on what chemical traits give rise to the best glues. In this report, we examine the simplest of these biomimetic polymers, poly[(3,4-dihydroxystyrene)-co-styrene]. Pendant catechol groups (i.e., 3,4-dihydroxystyrene) are distributed throughout a polystyrene backbone. Several polymer derivatives were prepared, each with a different 3,4-dihyroxystyrene content. Bulk adhesion testing showed where the optimal middle ground of cohesive and adhesive bonding resides. Adhesive performance was benchmarked against commercial glues as well as the genuine material produced by live mussels. In the best case, bonding was similar to that obtained with cyanoacrylate "Krazy Glue". Performance was also examined using low- (e.g., plastics) and high-energy (e.g., metals, wood) surfaces. The adhesive bonding of poly[(3,4-dihydroxystyrene)-co-styrene] may be the strongest of reported mussel protein mimics. These insights should help us to design future biomimetic systems, thereby bringing us closer to development of bone cements, dental composites, and surgical glues.     

Dendron–polymer conjugates via the diels–alder “click” reaction of novel anthracene‐based dendrons

Diblock and triblock dendron–polymer conjugates containing biodegradable polyester dendron blocks and polyethylene glycol (PEG) polymer were synthesized using the Diels–Alder “click” cycloaddition reaction. PEG polymers with furan‐protected maleimide functionality were synthesized and reacted with biodegradable polyester dendrons containing an anthracene moiety at their focal point. First through third generations of biodegradable polyester dendrons containing an anthracene unit at their focal point were synthesized using a divergent strategy. Efficient conjugation of the dendrons to polymers was demonstrated using ¹HNMR and size exclusion chromatography. This modular approach provides an easy access to the design of multivalent PEG conjugates. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 3191–3201     

仿贻贝粘附蛋白聚合物的研究及动态

贻贝粘附蛋白以其对不同基材表面及在水下都具备高强的粘附能力而闻名。根据仿生学原理,通过将贻贝粘附蛋白功能元即邻苯二酚基团与合成高分子相结合制备仿贻贝粘附蛋白聚合物,达到复制重现甚至超越天然贻贝粘附蛋白粘附效力的目的,是目前贻贝仿生领域研究热点之一。本文综述了近年来国内外仿贻贝粘附蛋白聚合物的研究进展。我们按照主链结构的种类进行了分类,对仿贻贝粘附蛋白聚合物材料的发展过程、材料的设计思路以及应用领域进行了系统的归纳总结。通过研究分子结构与仿生材料功能特性之间的相互关系,希望为以后设计合成新型的功能化的贻贝仿生材料提供有益的借鉴和参考。     

SiO2/聚合物核壳型杂化粒子及其空心结构的制备

SiO2/聚合物核壳型杂化粒子及其空心结构以其独特的形貌在药物控制释放、催化剂载体、生物医药等领域应用前景广阔,引起了人们的广泛关注。本文着重从乳液聚合法、仿生矿化法等制备方法角度阐述了SiO2/聚合物核壳型杂化粒子及其空心结构的研究进展。乳液聚合制备SiO2/聚合物核壳型杂化粒子简单易行,一般需要预先合成SiO2纳米粒子,其合成过程通常需要一些非理想的条件,如高温高压、极端pH、昂贵或有毒的有机试剂等,而且预先合成的SiO2粒子无法与聚合物实现100%匹配,即总有纯的聚合物粒子存在。相比之下,原位仿生矿化法制备SiO2杂化粒子不仅在环境条件下可进行,而且能够精确控制其纳米尺度的形态及分级有序结构。目前对材料科学家来讲,要使人工合成SiO2/聚合物杂化粒子实现像自然生物硅那样优异的性能,仍然是很大的挑战。     

Synthesis methods of organic two-dimensional materials

Among various two-dimensional (2D) materials, organic 2D polymers have attracted much attention, owing to their specific properties, such as lightweight, good flexibility, adjustable structure, and high adaptability. In recent years, more and more scientists have devoted to the research on their structural design, synthesis, characterization, and potential properties. However, in contrast to traditional one-dimensional (1D) and three-dimensional (3D) network macromolecules, the synthesis of 2D structures presents a challenge to polymer chemists, because polymerization usually takes place in a spatially random manner in solution-phase synthesis. In this review, we will focus on the synthesis methods of organic 2D materials, which have played a pivotal role since the beginning of the development of this field. We will highlight the representative examples according to the different types of polymers, including supramolecular organic 2D layers and covalent organic 2D polymers, and identify possible future research directions.     

Dendronized polymers via Diels–Alder “click” reaction

A modular approach toward the synthesis of polymers containing dendron groups as side chains is developed using the Diels–Alder “click” reaction. For this purpose, a styrene‐based polymer appended with anthracene groups as reactive side chains was synthesized. First through third‐generation polyester dendrons containing furan‐protected maleimide groups at their focal point were synthesized. Facile, reagent‐free, thermal Diels–Alder cycloaddition between the anthracene‐containing polymer and latent‐reactive dendrons leads to quantitative functionalization of the polymer chains to afford dendronized polymers. The efficiency of this functionalization step was monitored using ¹H and ¹³C NMR spectroscopy and FTIR and UV–vis spectrometry. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 410–416, 2010     

分子设计在热塑性弹性体制备中的应用

本文综述了近年来基于分子设计原理制备的热塑性弹性体的研究报道,包括提高聚氨酯热塑性弹性热稳定性和柔韧性;用立构可控茂金属催化剂制备聚丙烯热塑性弹性体;热可逆共价交联聚合物和星型结构、棕榈树结构、哑铃形结构聚合物的研究.同时对乳液互穿网络型热塑性弹性体以及热塑性弹性体共混物进行了简要介绍.     

Polymerization of Vinyl and Diene Monomers in Canal Complexes

In recent years the so-called biomimetic chemistry has received much attention. Studies of the preparation and design of functional polymers which can serve as polymeric enzyme and nucleic acid models appear to be a particularly rapidly expanding areas of research. These polymers and their aggregates should require highly specific sites or, in other words, atmospheres around them, in order to facilitate a series of selective reactions under conditions similar to those of biochemical environments. In this connection, molecular design of certain three-dimensional, highly organized spaces which consist of various sorts of molecular aggregates and can incorporate definite molecules in a specified way within their space are of interest for performing controlled organic and polymer synthetic reactions.     

Interfacing carbon nanotubes with living cells

We developed a polymer coating for carbon nanotubes (CNTs) that mimics the mucin glycoprotein coating of mammalian cells. CNTs coated with these mucin mimic polymers have two novel properties: they can bind to carbohydrate receptors, providing a means for biomimetic interactions with cell surfaces, and, importantly, they are rendered nontoxic to cells.