Significant advances have recently been made in the development of functional polymers that are able to undergo light-induced shape changes. The main challenge in the development of such polymer systems is the conversion of photoinduced effects at the molecular level to macroscopic movement of working pieces. This article highlights some selected polymer architectures and their tailored functionalization processes. Examples include the contraction and bending of azobenzene-containing liquid-crystal elastomers and volume changes in gels. We focus especially on light-induced shape-memory polymers. These materials can be deformed and temporarily fixed in a new shape. They only recover their original, permanent shape when irradiated with light of appropriate wavelengths. Using light as a trigger for the shape-memory effect will extend the applications of shape-memory polymers, especially in the field of medical devices where triggers other than heat are highly desirable.

Poly(arylene ether ketone)s containing sulfonate groups were synthesized by aromatic nucleophilic polycondensation of 4,4′-difluorobenzophenone (DFK), sodium 2,5-dihydroxybenzensulfonate (SHQ) and bisphenols. Only low-molecular weight oligomer was obtained when hydroquinone (HQ) was employed as comonomer, while copolymerization of DFK, SHQ, and phenolphthalein (PL) proceeded quantitatively to high-molecular weight (reduced viscosities above 0.68dL/g) in dimethylsulfoxide at 175°C in presence of anhydrous potassium carbonate. The sulfonated polymers were soluble in dipolar aprotic solvents, such as N,N-dimethylactamide and N-methyl-2-pyrrolidinone. Tough membranes cast from N,N-dimethylformamide solution with SHQ/DFK mole ratios ≤65:35 were obtained. Both glass transition temperatures and hydrophilicity of the copolymers increased with the content of sodium sulfonate groups. The materials are candidates as new polymeric electrolytes for proton exchange membranes.

Polymers see the light When a plant moves its leaves to face sunlight, it is using light as directional information. Now a synthetic polymer with similar functionality to this biological system has been produced. An object made from this light-sensitive ‘shape memory polymer’ can be deformed to a new temporary shape, then fixed in that shape by light of the right wavelength. The molecular switches in this material are photosensitive groups that connect with and disconnect from each other in response to light of different wavelengths. Polymeric materials with light-induced shape-memory could find application in medical devices, microsystem technology and intelligent surface engineering.

Die vorliegende Erfindung betrifft amorphe photosensitive Netzwerke. Die Netzwerke zeichnen sich durch gute Form-Gedachtnis-Eigenschaften aus.

采用基质辅助激光解吸电离飞行时间质谱(MALDI-TOF-MS)技术分别对2种合成的聚芳醚酮环状低聚物进行了分析研究,并讨论了低聚物中不同聚合度离子组分的分布规律.实验结果表明MALDI-TOF-MS是分析环状低聚物直观、准确、快速的分析工具.

Novel macrocyclic aryl thioether ester oligomers have been synthesized in high yield from phthaloyl dichloride and 4,4′-thiodiphenol under pseudo high dilution conditions. The cyclic nature was unambiguously confirmed by a combination of MALDI-TOF MS, gel permeation chromatography and NMR analyses. Single-crystal X-ray diffraction of cyclic ester dimer reveals no severe strain on the cyclic structure. The free-radical ring opening polymerization (ROP) of the macrocyclic oligomers was achieved to give high molecular weight polymers via a transthioetherification reaction. The molecular weight of the polymer resulting from ROP decreases as the conversion of cyclic oligomers increases after a polymerization period of 30 min.

Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) was used to identify cyclic(aryl ether ketone) oligomers, using 2,5-dihydroxybenzoic acid as a matrix, and Na+ and K+ as cationization agents, The existence of different ring-sized cyclic oligomers up to 9 and their distribution were determined and compared with GPC results, The results indicated that MALDI-TOF MS was a powerful and rapid analytical tool for the cyclic oligomers.

Some novel macrocyclic (arylene ether sulfone) containing cardo groups and (arylene ether ketone sulfone) oligomers have been synthesized in high yields by a nucleophilic aromatic substitution reaction of 4,4'-difluorophenylsulfone with bisphenols in the presence of anhydrous potassium carbonate under a pseudo-high-dilution condition. Detailed structural characterization of these oligomers by matrix-assisted laser desorption/ionization-time of flight-mass spectrometry (MALDI-TOF-MS), fast atom bombardment mass spectrometry (f.a.b.-m.s.), nuclear magnetic resonance spectrometry (n.m.r.) and single-crystal X-ray structure analysis confirms their cyclic nature, and the composition of the oligomeric mixtures is provided by g.p.c. analysis. Ring polymerization of cyclic oligomers 3a to a high molecular weight polymer with M-w of 59.1 k was achieved by heating at 290 degrees C for 40 min in the presence of a nucleophilic initiator. (C) 1998 Elsevier Science Ltd. All rights reserved.

A novel macrocyclic arylene ether ketone oligomer has been synthesized and its structure was unambiguously characterized by 1H and 13C NMR technology. The assignments of 1H and 13C NMR were further confirmed by 2D 1H- 1H COSY and 13C- 1H COSY methods, as well as by comparison with the standard spectra of similar compounds.

Novel cyclic aryl ether sulfone oligomers have been synthesized in high yield based on bisphenol A and 4-fluoro-3-nitrophenyl sulfone firstly through interfacial polycondensation reaction under a pseudo-high-dilution condition. Detailed structural characterization of the oligomers by MS, GPC, NMR and IR analyses confirmed the cyclic nature.

Two kinds of macrocyclic oligomers containing aromatic sulfide linkages have been synthesized by the solution polycondensation in high yield. The cyclic compounds were characterized by H-1 and C-13 NMR, by and MALDI - TOF MS.

A series of new macrocyclic arylates have been efficiently synthesized and unambiguously characterized by a combination of GPC, MS(FAB) and H-1 NMR. These macrocycles undergo facile ring-opening polymerization in the presence of anionic initiators to give high molecular weight polyarylates.

Some novel macrocylic(arylene ether ketone)oligomers were synthesized in high yields by a nucleophilic aromatic substitution reaction of 4,4′-dinitrobenzophenone with bisphenols in the presence of anhydrous potassium carbonate under pseudo-high-dilution conditions. Detailed structural characterization of these oligomers by matrix-assisted laser desorption/ionization-time of fiight-mass spectrometry (MALDI-TOF-MS), 1H NMR and FT-IR confirmed their cyclic nature and the compositions of the oligomeric mixtures was indicated by GPC analysis. Ring-opening polymerization of cyclic oligomers 3a to a high molecular weight polymer with Mw of 52.3 and Mn of 17.2 k was achieved by heating at 280°C for 40 min in the presence of a nucleophilic initiator.

Macrocyclic arylene ether ketone dimer was isolated from a mixture of cyclic oligomers obtained by the nucleophilic substitution reaction of bisphenol A and 4,4'-difluorobenzophenone and easily polymerized to high molecular weight linear poly(ether ketone). The cyclic compound was characterized by FTIR, H-1- and C-13-NMR, and single-crystal x-ray diffraction. Analysis of the spectral and crystal structure reveals extreme distortions of he phenyl rings attached to the isopropylidene center and of the turning points of the molecular polygons. The release of the ring strain on ring-opening combined with entropical difference between the linear polymer chain and the more rigid macrocycle at temperatures of polymerization may be the proposed motivating factors in the polymerization of this precursor to high molecular weight poly(ether ketone). (C) 1997 John Wiley & Sons, Inc.

A series of macrocyclic arylate dimers have been selectively synthesized by an interfacial polycondensation of o-phthaloyldichloride with bisphenols. A combination of GPC, FAB-MS,1H and13C NMR unambiguously confirmed the cyclic nature. Although single-crystal X-ray analysis of two such macrocycles reveals no severe strain on the cyclic structures, these macrocycles can undergo facile melt polymerization to give high molecular weight polyarylates.

ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorNEXTNovel Macrocyclic Precursors of Phenolphthalein Poly(arylene ether ketone) and Poly(arylene ether sulfone): Synthesis and PolymerizationHongyan Jiang, Tianlu Chen, Shuqin Bo, and Jiping XuView Author Information Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022, P. R. China Cite this: Macromolecules 1997, 30, 23, 7345–7347Publication Date (Web):November 17, 1997Publication History Received12 June 1997Revised3 September 1997Published online17 November 1997Published inissue 1 November 1997https://doi.org/10.1021/ma970857pCopyright © 1997 American Chemical SocietyRequest reuse permissionsArticle Views317Altmetric-Citations19LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit Read OnlinePDF (155 KB) Get e-AlertscloseSUBJECTS:Ethers,Gel permeation chromatography,Oligomers,Polymers,Viscosity Get e-Alerts