Name: synthesis of cyclic polymers and characterization of their diffusive motion in the melt state at the single molecule level
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This work was supported by a Grant-in-Aid for Scientific Research No. 22750122 (S.H.), No. 26288099 (T.Y.), and No. 23350050 (Y.T.) of the Japan Society for the Promotion of Science. S.H. is grateful for The Kurata Memorial Hitachi Science and Technology Foundation. The research reported in this publication was supported by the King Abdullah University of Science and Technology (S.H.).

1.单功能和双功能合成聚（THF） <ol><li> 单官能聚（THF）中 <ol><li>火焰干燥的2颈100毫升圆底烧瓶中。真空和填充氮气（3次）的烧瓶中。 </li><li>蒸馏的四氢呋喃（THF）（50毫升）添加到该烧瓶中。把烧瓶的水浴中在20℃和平衡的温度。 </li><li>通过注射器甲基三氟甲磺酸酯（0.5毫摩尔）添加到该烧瓶中。搅拌在20℃下5-10分钟的混合物。 </li><li>通过注射器加入正 -苯基吡咯烷（4-6当量）的烧瓶中。搅拌30-60分钟该混合物。 </li><li>在减压（ 约 100托）完全除去溶剂。溶解残留物在3-5毫升丙酮中。丙酮溶液加入到300-500毫升正己烷的。过滤沉淀物，并减压干燥。 </li></ol></li><li> 双官能的聚（四氢呋喃） <ol><li>火焰干燥的2颈100毫升圆底烧瓶中。弗吉尼亚州cuum和填充氮气（3次）的烧瓶中。 </li><li>蒸馏过的THF（50毫升）添加到该烧瓶中。把烧瓶的水浴中在20℃和平衡的温度。 </li><li>通过注射器添加三氟甲磺酸酐（0.3毫摩尔）至该烧瓶中。搅拌在20℃下5-10分钟的混合物。 </li><li>通过注射器加入正 -苯基吡咯烷（4-6当量）的烧瓶中。搅拌30-60分钟该混合物。 </li><li>在减压（ 约 100托）完全除去溶剂。溶解残留物在3-5毫升丙酮中。丙酮溶液加入到300-500毫升正己烷的。过滤沉淀物，并减压干燥。 </li></ol></li></ol> 2.苝的合成二酰亚胺注册成立的4星武装和8字形双环聚（THF） <ol><li> 臂的星形聚（THF）中 <ol><li> 离子交换 <ol><li>溶于水（10毫克/毫升，150毫升）中的苝酰亚胺四甲酸二钠盐。溶解在丙酮单官能聚（THF）（160毫克/毫升，4ml）中。添加丙酮溶液逐滴加入剧烈搅拌的水溶液。通过过滤收集形成的沉淀。 </li><li>重复上述过程以将回收的沉淀物（2.1.1.1）的四倍。 </li></ol></li><li> 共价固定 <ol><li>溶解在甲苯中所获得的沉淀物（5毫克/毫升）。回流4小时的溶液中。 </li><li>在减压（ 约 100托）完全除去溶剂。通过硅胶用正己烷 /丙酮（2/1体积/体积）的插头过滤残余物。将溶液加入到冰冷却的水（300-500毫升）以沉淀产物。通过过滤收集沉淀物。 </li></ol></li></ol></li><li> 二环8字形聚（THF）中 <ol><li> 离子交换 <ol><li>溶解在水（6毫克/毫升，50ml）中的苝酰亚胺四甲酸二钠盐。溶解双官能的聚（四氢呋喃）（0.5克）在30-50毫升丙酮。添加丙酮溶液滴加到在0℃下剧烈搅拌的水溶液。通过过滤收集形成的沉淀。 </li><li>重复上述过程以将回收的沉淀物（2.2.1.1）。 </li></ol></li><li> 共价固定 <ol><li>溶解在甲苯中所获得的沉淀物（0.05克/升）。回流4小时的溶液中。 </li><li>在减压（ 约 100托）完全除去溶剂。添加甲苯，以部分溶解残留物。再沉淀成300-500毫升正己烷的。 </li><li>通过硅胶用正己烷 /丙酮（2/1体积/体积）的插头过滤形成的沉淀。重新沉淀到300-500毫升的水。 </li><li>纯化通过柱色谱法18使用聚苯乙烯凝胶所形成的沉淀物。用CHCl 3洗脱剂，对物进一步纯化用制备凝胶渗透色谱（GPC）粗产物19OVE副产物通过监测折射率（RI）和UV检测器。 </li></ol></li></ol></li></ol> 3.单分子荧光成像实验<ol><li> 样品制备 <ol><li> 显微镜盖玻片清洗 <ol><li>地方第1.5 24 x 24毫米显微镜盖玻片在染色缸。 </li><li>添加1M的氢化钾溶液（100ml）中放入罐子和超声处理15分钟。倒出通过倾析的氢氧化钾溶液和冲洗用的超纯水的盖玻片数次。添加光谱级乙醇（100ml）插入罐子和超声处理15分钟。 </li><li>倒出通过倾析乙醇和漂洗用超纯水的盖玻片数次。通过倾析倒出关闭超纯水之后，重复步骤3.1.1.2。 </li><li>添加超纯水的罐子和超声处理15分钟。用超纯水多次盖玻片。用塑料镊子取出从罐子盖玻片，并且由干燥的空气或干燥的氮气干燥。 </li></ol></li><li> 聚合物熔体样品14,15的研制 <ol><li>在玻璃瓶中加入100μl非标记的线性聚（THF）中，并加热到使用吹风机的熔点（约25℃）以上的温度。 </li><li>溶解荧光团并入聚合物（线性，4臂的星形的，环状的，或8字形二环在2.1和2.2合成）在氯仿（1毫升，10 -6 M）。加入1微升溶液到100微升的非标记的线性聚（THF）中的熔融的。 </li><li>彻底将样品与一个枪头混合后，通过使用干燥机加热样品蒸发氯仿。 注意:此提供含有荧光团引入聚合物的10 -8 M的非标记的线性聚（THF）中的熔体。 </li><li>采取用微型移液器以及d样品的10微升ROP它在清洁的盖玻片。把在样品另一清洗盖玻片夹心两个盖玻片之间的样本。 </li><li>轻轻按下用塑料镊子样品。 </li></ol></li></ol></li><li> 宽视场荧光成像设置15 <ol><li> 激励激光器（488纳米）的引入倒置显微镜的背面端口 <ol><li>插入一个励磁带通滤波器和起偏器进入光束路径。 </li><li>由光束扩展器扩大光束的直径约1厘米。 </li><li>插入一个四分之一波板进入光束路径。在45度的相对于该偏振片的设置波片的光轴。可替代地，插入Berek补偿，并设置光延迟λ/ 4。 </li><li>插入在激励光束路径的膜片来调整光束的大小。 </li><li>前引入的激光束进入倒置光学microsco的背面端口PE，插入一个聚焦透镜（平面凸透镜，焦距≈300毫米）在激光束出物镜的被准直的位置上。 </li></ol></li><li>反射用安装在过滤器立方体的分色镜的激光束后，通过高数值孔径（NA）的物镜引入的激光束到样品（ 例如，NA 1.3，放大100倍，浸油）。 </li><li>附加一个目标加热器到物镜和设定温度至30℃。 </li><li> 安装样品在倒置显微镜的阶段 <ol><li>滴在物镜上浸油一滴和安装在显微镜状态的样品。 </li><li>确保约10微米的样品的厚度是通过检查样品的底部和顶部表面的轴向位置得到的。 </li><li>调整显微镜的焦点到样品的底面之上几微米。 </li></ol></l我&gt; <li> 物镜下获得圆偏振光激发光 <ol><li>插入一个偏振器成准直的激光束出物镜。 </li><li>记录由偏振后插入一个功率计透过偏振片传输的激光的强度。通过旋转偏振器记录在不同的偏振角的发射激光功率。 </li><li>如果发射的激光功率是不是在所有的偏振角恒定，稍微旋转插在激发射束路径的四分之一波片或Berek补偿。 </li><li>重复步骤3.2.5.2 3.2.5.3和直到恒发射激光功率在所有的极化角获得。确保该圆偏振光在样品中获得。 </li></ol></li><li> 设置的EM（电子乘法） -电荷藕合器件（CCD）摄像机 <ol><li>在EM-CCD相机连接到显微镜的侧端口，并将其连接到t他的图像采集软件。 </li><li>如果需要的话，通过发送由EM-CCD照相机的设备所产生的晶体管 - 晶体管逻辑（TTL）信号同步照相机暴露于机械快门或插在激发射束路径的声光可调滤波器。可替代地，通过发送由EM-CCD照相机的激光器产生的TTL信号同步照相机暴露于激光输出。 注意:只有在一个固态激光器，其输出功率可以通过输入晶体管 - 晶体管逻辑来调制用于实验（TTL）信号后一种选择是适用的。 </li><li>施加EM增益（通常为约300），以使用软件控制相机以获得单荧光团的高品质的荧光图像的CCD照相机。 </li><li>设定感兴趣区域（ROI）的区域使用软件控制照相机（在视场的中心通常为128×128像素）。 注意:这允许意马在帧传输模式，这是需要用于可视化熔融样品中的荧光团引入聚合物链的运动200赫 - 在100的帧速率纳克实验。 </li></ol></li></ol></li><li> 运行试验 <ol><li> 优化实验条件 <ol><li>利用插入在激励光束路径隔膜调整样本的照明区域到大约20微米的直径。 </li><li>通过手动选择插入在激发束路径的适当的中性密度（ND）滤光器8毫瓦 - 在样品4中设置的激发激光功率。 注:此为1的平均激光功率- 2千瓦厘米-2的样本。 </li><li> 200赫兹 - 在100的帧速率的样本的记录荧光图像。如果从各荧光团并入聚合物中得到的荧光强度过低，使用第逐渐增加的激励功率ËND滤镜，直到样品达到约100毫瓦。 </li><li>如果单分子荧光图像的质量仍不能令人满意，通过记录的非标记的聚（四氢呋喃）的纯熔体荧光图像检查样品中的荧光杂质。在高荧光背景观察的情况下，使用不同的非标记的聚（THF）中。 </li><li>如果在熔体从荧光团并入聚合物中得到的荧光斑点的密度太高，以在空间上隔离它们（这将导致在扩散运动的分析错误），降低样品直至荧光团引入聚合物的浓度空间隔离的斑点观察。 </li><li>如果在熔体从荧光团并入聚合物中得到的荧光斑点的密度太低（这会导致成像实验的低吞吐量），增加样品中的荧光团引入聚合物的浓度直到appropr到达荧光点的莱特密度。 </li><li>如果从熔融物中的荧光团并入聚合物中得到的荧光图像被模糊，提高了成像采集的帧速率。 注:这通常需要一个小的投资回报率，通常为64×64像素。 </li></ol></li></ol></li><li> 图像采集 <ol><li>一旦实验条件进行了优化，离开显微镜舞台上所安装的样品为一个小时，使样品达到平衡的条件。 </li><li>记录500 - 在熔融状态下的荧光团引入聚合物的1000荧光图像序列在100 - 200赫兹帧频。如果默认的文件格式不TIFF，所有的图像序列转换为TIFF格式。 </li></ol></li></ol> 4.扩散运动分析<ol><li> 均方位移（MSD）分析 <ol><li>裁剪荧光图像序列以这样的方式每个图像序列包含单个和良好聚焦扩散荧光团结合使用的聚合物的图像处理软件，如ImageJ的。 </li><li>当裁切后的图像序列包含超过10帧，分割图像序列成多个序列，每个序列包含10帧。 </li><li>准确的图像的二维高斯拟合确定在每个图像序列的分子的位置。 </li><li>确定使用方程式20的扩散系数（D）的单个分子通过扩散轨迹（分子即时间依赖性的位置）的均方位移（MSD）分析 <img alt="公式1" src="/files/ftp_upload/54503/54503equation1.jpg" /> 其中，x i和Y I是在图像帧i的分子的位置，并且n在帧i表示与时间经过Δt的帧号。 </li><li>情节扩散系数频率直方图。 注:通常，直方图从超过100个分子构成。 </li></ol></li><li> 累积分布函数（CDF）的分析 注:CDF，P（R 2，IΔt）的对应于一定的时间差Iδ 吨后发现从原点的半径r内扩散分子的累积概率。 <ol><li>计算过程中出现的时间滞后1Δt，2Δt，····，iΔt为4.1.3中获得的所有扩散轨迹平方位移。 注意:这些计算给总M I平方位移的时间滞后iΔt的。 </li><li>计算在不同R 2值比R 2小的总M I数据集内平方位移（L I）的数字（0 &lt;R2 &lt;∞）。归L I VS R 2<html>地块对应CDF，P（R 2，iΔt）。 </li></ol></li><li> 两者结合起来分析具有鲜明的扩散模型 注:获得CDF是由不同的扩散模型拟合;均匀扩散模型，其中对D分布通过高斯（单高斯模型）中所描述的多个扩散模式和多个扩散模式，其中对D分布由多个高斯（多高斯模型）中所述。 <ol><li>在均匀扩散模型，确定平均D将使用公式21拟合CDF <img alt="方程2" src="/files/ftp_upload/54503/54503equation2.jpg" /> 注意:从等式任何偏差暗示该分子的异质扩散。 </li><li>在单高斯模型，确定一高斯（F（D））中所述通过拟合使用15 CDF D的概率分布 ON3"SRC ="/文件/ ftp_upload / 54503 / 54503equation3.jpg"/&gt; <img alt="公式4" src="/files/ftp_upload/54503/54503equation4.jpg" /> 其中A，W和D 0是振幅，宽度和高斯的中心。 </li><li>在双高斯模型，通过拟合使用14 CDF确定j 个由高斯（F（D））中所描述的D分量的概率分布 <img alt="Equation5" src="/files/ftp_upload/54503/54503equation5.jpg" /> <img alt="公式6" src="/files/ftp_upload/54503/54503equation6.jpg" /> 其中，A j是每个扩散组分的分数，并且αJ，w j的和D 0 j是幅度，宽度，和第 j 个高斯分量的中心。 </li></ol></li><li> 理论概率DISTRI计算扩散系数的bution 注:D的发生是由于统计误差（P（D）D D）基于上不同的扩散模式的概率分布;均匀扩散模型，其中对D分布通过高斯（单高斯模型）中所描述的多个扩散模式和多个扩散模式，其中对D分布由多个高斯（多高斯模型）中所述。 <ol><li>在均质扩散模型，使用等式22计算D的统计概率分布 <img alt="Equation7" src="/files/ftp_upload/54503/54503equation7.jpg" /> 其中N是数据点的一个扩散的轨迹的数量（N = 10，见4.1.2）中，D 0是平均扩散系数（由CDF分析确定，见4.2.3.1），D是实验获得的针对单独的轨迹扩散系数。 </li><li>在里面单一高斯扩散模型，使用等式15计算D的统计概率分布 <img alt="Equation8" src="/files/ftp_upload/54503/54503equation8.jpg" /> 其中f（D）表示由CDF分析测定的D概率分布（见4.2.3.2）和D 0是平均扩散系数（由CDF分析确定，见4.2.3.2）。 </li><li>在双高斯扩散模型，使用等式14计算D的统计概率分布 <img alt="公式9" src="/files/ftp_upload/54503/54503equation9.jpg" /> 其中f（D j）表示第 j 个由CDF分析确定D（D，J）的成分的概率分布（见4.2.3.3）和D 0J是第 j 个成分（由CDF测定的平均扩散系数分析见4.2.3.3）。 </li></ol></li></ol>

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J. 65 (5), 2021-2040 (1993).</li><li>Schutz, G. J., Schindler, H., Schmidt, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Single-molecule+microscopy+on+model+membranes+reveals+anomalous+diffusion.">Single-molecule microscopy on model membranes reveals anomalous diffusion.</a> Biophys. J. 73 (2), 1073-1080 (1997).</li><li>Vrljic, M., Nishimura, S. Y., Brasselet, S., Moerner, W. E., McConnell, H. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Translational+diffusion+of+individual+class+II+MHC+membrane+proteins+in+cells.">Translational diffusion of individual class II MHC membrane proteins in cells.</a> Biophys. 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The authors have nothing to disclose.

4武装和8字形聚合物进行经由ESA-CF协议（ 图1），它是用于合成的关键步骤制备。12,24的单官能和双官能的线性聚（四氢呋喃）■用N- -phenylpiperidinium端基根据前述方法合成11的离子交换是通过用三氟甲磺酸酯抗衡聚合物前体的丙酮溶液的再沉淀进行到含羧酸盐的过量的水溶液。 对于4臂的星形聚合物的离子交换产物的共价转化在甲苯（4.9克/升）回流4小时进行。如果转换不充分，延长反应时间。用硅胶柱色谱法用丙酮/ 正己烷和再沉淀于水中得到的共价键合产品。 4武装聚合物的1 H NMR示于图2a。氏小号ESA-CF程序允许环状聚合物的有效合成。然而，该协议被限制为具有环状鎓末端基团的聚合物。 为8字形聚合物产物，该反应在甲苯中在回流下稀释（0.2克/升）中进行4小时，导致了不溶性级分的大部分的形成，这可能是由于分子间的反应产物。可溶性部分再沉淀在正己烷 ，进行硅胶柱层析，用丙酮/ 正己烷 ，并在水中再沉淀。得到的粗产物进行用大小排阻珠粒柱层析并回收GPC以允许8字形聚合物产物的分离。 8形聚合物的1 H NMR示于图2b。此ESA-CF协议可以适用于进一步复杂拓扑的聚合物。 高品质的荧光图像essenti人的分子的扩散运动的准确的分析。 1）荧光杂质是存在于样品中时，荧光图像被显著恶化，2）一种掺入荧光团的荧光量子产率低，以及3）成像的帧速率小于聚合物分子的扩散运动慢。设定低于室温的温度（20℃）或高于37℃，会造成折射率不匹配，这也将恶化记录荧光图像的质量。使用安装在一过滤器立方体一较窄频带发射带通滤波器的某个时候提高了荧光图像的质量。因为在成像实验中使用的EM-CCD照相机的曝光时间通常限制在毫秒，扩散运动超过此时间尺度速度不能用这种方法捕获。 的在MSD分析的统计误差的效果评价为fo的关键步骤r是异质扩散的特征。统计误差应通过讨论异质扩散之前计算使用均匀扩散模型22的扩散系数的概率分布进行仔细的评估。异构扩散也应由CDF分析进行仔细的评估。当两者结合起来显示来自均匀扩散模型（ 即单指数衰减曲线）明确的偏差，这表明多个扩散成分的存在。异质扩散的定量表征需要综合MSD，CDF和概率分布分析。14,15 聚合物动力学，包括扩散运动，已经确实描述为在常规方法如核磁共振，7光散射，8和粘度测量整体平均值。9，由SINGL揭示异构扩散运动电子分子成像16常常是非常困难的整体平均的方法来检测。考虑聚合物的固有异质性质，25-27在这个协议中报道的方法并不限于拓扑聚合物的表征，但也适用于各种缠结条件下的聚合物。28此外，在该协议报告的方法将找到在复杂的系统中，如通过孔材料分子扩散异构扩散的分析具有广泛的应用。29

Cyclic polymers are unique in that they do not have chain ends. They often exhibit unusual behaviors which is distinct from their linear counterpart, including increased thermal stability of polymer micelles by a linear-to-cyclic conversion,1,2 and spatial organization of DNA in bacterial cells by a loop formation.3 Topological interactions between the cyclic chains are believed to be the critical factor for such unusual behaviors.4,5 Therefore, characterizing the motion and relaxation of cyclic polymers under entangled conditions has been an important research topic in polymer science for decades.6
Cyclic polymer dynamics has been investigated using both synthetic and naturally occurring molecules by means of ensemble averaged experimental methods such as nuclear magnetic resonance (NMR), light scattering, and viscosity measurements.7-9 However, these studies often suffer from impurity molecules in the samples.10 Furthermore, spatiotemporal heterogeneities of the motion of individual molecules caused by inherent structural heterogeneity of entangled polymers are often hidden behind the ensemble averaging in these studies. In order to characterize molecular level dynamics of cyclic polymers, a synthesis method that provides high purity cyclic polymers and an experimental and analysis methods that allow for quantitative characterization of molecular motion at the single molecule level have to be developed. Here, we will show a method to synthesize high-purity cyclic and dicyclic poly(THF)s that incorporate a fluorophore unit using an electrostatic self-assembly and covalent fixation (ESA-CF) process11-13 and a method to analyze the motion of the individual fluorophore-incorporated polymer chains using a combination of mean-squared displacement (MSD) and cumulative distribution function (CDF) analyses.
A proper data processing has been shown to be essential for the accurate characterization of the diffusive motion. With an adequate MSD and CDF analyses, a multiple-mode diffusion of the cyclic and dicyclic polymers in the melt and semi-dilute solution of the linear polymer chains has been revealed,14-16 suggesting the significant effects of the topological states of the polymers on the diffusive motion of the chains under entangled conditions.17 While the experimental and analytical approaches to characterize the motion of the cyclic polymers are described in this protocol, the same method can be used to quantitatively characterize the diffusive motion in many other heterogeneous systems. The approach would be especially suitable when multiple diffusion components existing in the samples are to be analyzed.

<table><tbody><tr><td>&lt;strong&gt;Materials&lt;/strong&gt;</td><td></td><td></td><td></td></tr><tr><td>THF</td><td>Godo</td><td></td><td></td></tr><tr><td>Wakosil C-300</td><td>Wako Pure Chemical Industries</td><td></td><td></td></tr><tr><td>Acetone</td><td>Godo</td><td></td><td></td></tr><tr><td>Toluene</td><td>Godo</td><td></td><td></td></tr><tr><td>&lt;em&gt;n&lt;/em&gt;-Hexane</td><td>Godo</td><td></td><td></td></tr><tr><td>CHCl&lt;sub&gt;3&lt;/sub&gt;</td><td>Kanto Chemical</td><td></td><td></td></tr><tr><td>Bio-Beads S-X1</td><td>Bio-Rad</td><td></td><td></td></tr><tr><td>Methyl triflate</td><td>Nacalai Tesque</td><td></td><td></td></tr><tr><td>Triflic anhydride</td><td>Nacalai Tesque</td><td></td><td></td></tr><tr><td>Potassium Hydroxide</td><td>Wako Pure Chemical Industries</td><td></td><td></td></tr><tr><td>Ethanol</td><td>Wako Pure Chemical Industries</td><td></td><td></td></tr><tr><td>Poly(tetrahydrofuran)</td><td>Aldrich</td><td></td><td></td></tr><tr><td>Chloroform</td><td>Wako Pure Chemical Industries</td><td></td><td></td></tr><tr><td>Immersion oil</td><td>Cargille</td><td>Type 37 / Type A</td><td></td></tr><tr><td>&lt;strong&gt;Equipment&lt;/strong&gt;</td><td></td><td></td><td></td></tr><tr><td>2-Neck 100-ml round-bottom flask</td><td></td><td></td><td></td></tr><tr><td>Flask</td><td></td><td></td><td></td></tr><tr><td>Beaker</td><td></td><td></td><td></td></tr><tr><td>Funnel</td><td></td><td></td><td></td></tr><tr><td>Filter paper</td><td>Whatman</td><td></td><td></td></tr><tr><td>Reflux condenser</td><td></td><td></td><td></td></tr><tr><td>Syringe</td><td></td><td></td><td></td></tr><tr><td>Water bath</td><td></td><td></td><td></td></tr><tr><td>Magnetic stirrer</td><td></td><td></td><td></td></tr><tr><td>Rotary evaporator</td><td></td><td></td><td></td></tr><tr><td>Microscope cover slips (24 x 24 mm, No. 1)</td><td>Matsunami Glass</td><td>CO22241</td><td></td></tr><tr><td>Staining jar</td><td>AS ONE Corporation</td><td>1-7934-01</td><td></td></tr><tr><td>Ultrasonic cleaner</td><td>VWR International&amp;nbsp;</td><td>142-0047</td><td></td></tr><tr><td>Inverted microscope</td><td>Olympus</td><td>IX71</td><td></td></tr><tr><td>Ar-Kr ion laser</td><td>Coherent</td><td>Innova 70C</td><td></td></tr><tr><td>Berek compensator</td><td>Newport</td><td>5540</td><td></td></tr><tr><td>Excitation filter</td><td>Semrock</td><td>LL01-488-12.5</td><td></td></tr><tr><td>Dichloric mirror</td><td>Omega optical</td><td>500DRLP</td><td></td></tr><tr><td>Emission filter</td><td>Semrock</td><td>BLP01-488R-25</td><td></td></tr><tr><td>Lens and mirror</td><td>Thorlabs</td><td></td><td></td></tr><tr><td>EM-CCD camera</td><td>Andor Technology</td><td>iXon</td><td></td></tr><tr><td>Objective lens (100X, N.A. = 1.3)</td><td>Olympus</td><td>UPLFLN 100XOP</td><td></td></tr><tr><td>Objective heater</td><td>Bioptechs</td><td></td><td></td></tr><tr><td>Preparative GPC</td><td>Japan Analytical Industry</td><td>LC-908</td><td></td></tr></tbody></table>

synthesis of cyclic polymers and characterization of their diffusive motion in the melt state at the single molecule level

We demonstrate a method for the synthesis of cyclic polymers and a protocol for characterizing their diffusive motion in a melt state at the single molecule level. An electrostatic self-assembly and covalent fixation (ESA-CF) process is used for the synthesis of the cyclic poly(tetrahydrofuran) (poly(THF)). The diffusive motion of individual cyclic polymer chains in a melt state is visualized using single molecule fluorescence imaging by incorporating a fluorophore unit in the cyclic chains. The diffusive motion of the chains is quantitatively characterized by means of a combination of mean-squared displacement (MSD) analysis and a cumulative distribution function (CDF) analysis. The cyclic polymer exhibits multiple-mode diffusion which is distinct from its linear counterpart. The results demonstrate that the diffusional heterogeneity of polymers that is often hidden behind ensemble averaging can be revealed by the efficient synthesis of the cyclic polymers using the ESA-CF process and the quantitative analysis of the diffusive motion at the single molecule level using the MSD and CDF analyses.

苝二酰亚胺-掺入4臂的星形和8字形二环聚（四氢呋喃）■用的静电自组装和共价固定（ESA-CF）的过程（ 图1， 图2）合成的。测量时间推移单分子荧光图像为4武装（ 图3a）和8字形（ 图3b）的聚合物。时间推移荧光图像（ 图3）显示空间隔离的清晰明亮的斑点是由于高荧光苝酰亚胺荧光团23的纳入链。计算的扩散系数的频率直方图为4武装（ 图4a）和8字形（ 图4b）由时间推移图象的均方位移（MSD）分析聚合物。 MSD地块和两者结合起来的计算是使用MATLAB写的程序进行。拟合从实验中获得的两者结合起来的是用数据处理软件，如原产地临进行。通过将MSD分析确定扩散系数的频率直方图显示广泛分布（ 图4）从两个扩散的分析和异质性的统计误差所得。频率直方图示出了从该均匀扩散模型清晰的偏差，这表明在聚合物分子的异质扩散（ 图4中绿线）。14累积分布函数（CDF）分别计算的4-武装（ 图5a）和8形（ 图5b）的聚合物和由单一的高斯（ 图5a）装配并双高斯（ 图5b）的模型。计算扩散系数的统计概率分布为4武装（ 图4a）和8字形（ 图4b）聚合酶<html>由单一高斯，或双高斯模型ymers。单（ 图5a）和双（ 图5b）的高斯模型拟合实验获得的CDF好。这些结果表明，4-武装聚合物的扩散由扩散系数的广泛分布来描述，而8字形聚合物显示两个不同的扩散模式。 <img alt="图1" src="/files/ftp_upload/54503/54503fig1.jpg" /> 图1.苝酰亚胺注册成立的聚合成路线（THF）第 （ 一 ）4臂的星形聚合物和（b）8字形双环聚合物的合成路线。 <a href="https://www.jove.com/files/ftp_upload/54503/54503fig1large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <html> 54503fig2.jpg"/&gt; 图2.表征合成聚合物。（ 一 ）4臂的星形聚合物和（b）8字形双环聚合物的NMR谱。 <a href="https://www.jove.com/files/ftp_upload/54503/54503fig2large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <img alt="图3" src="/files/ftp_upload/54503/54503fig3.jpg" /> 图3（动画）。在非标记线性聚熔体苝二酰亚胺-掺入聚（四氢呋喃）第 （ 一 ）4臂的星形聚合物和（b）的时间推移的荧光图像的单分子荧光成像 8字形二环聚合物（THF ）。比例尺=5μm以下。请点击此处观看电影<a href="https://www.jove.com/files/ftp_upload/54503/Figure_3a_submit.mov" target="_blank">（一）</a>和3 / Figure_3b_submit.mov"目标="_空白"&gt;（B）。 <img alt="图4" src="/files/ftp_upload/54503/54503fig4.jpg" /> 图4.苝二酰亚胺-掺入聚MSD分析（THF）S扩散在熔体中。在熔体个体（ 一个 ）4-臂的星形聚合物和（b）8字形二环聚合物确定扩散系数的频率直方图的非标记的线性聚（THF）中。实线表示理论计算基于三个不同的扩散模式的扩散系数的概率分布;均匀扩散模型（绿线，见4.3.1），单高斯模型（红线，见4.3.2），和双高斯模型（蓝线，见4.3.3）。14 <a href="https://www.jove.com/files/ftp_upload/54503/54503fig4large.jpg" target="_blank">，请点击这里查看这个大版本数字。</a> 在1-P为（ 一 ）4臂的星形聚合物的形式- 苝酰亚胺掺入的聚（四氢呋喃）的图5的CDF分析š扩散在熔融实验得到累积分布函数（75毫秒iΔt= 7.5）。和（b）在非标记线性聚（THF）中的熔融8字形双环聚合物。虚线显示有（一）4.2.3.2及（b）方程等式配件在4.2.3.3。14 <a href="https://www.jove.com/files/ftp_upload/54503/54503fig5large.jpg" target="_blank">，请点击此处查看该图的放大版本。</a>

Watch this Scientific Journal Video about Synthesis of Cyclic Polymers and Characterization of Their Diffusive Motion in the Melt State at the Single Molecule Level at JoVE.com

Synthesis of Cyclic Polymers and Characterization of Their Diffusive Motion in the Melt State at the Single Molecule Level

一种用于合成和在单分子水平的环状聚合物的扩散运动的表征协议提出。

环状聚合物的合成及其在熔融状态扩散运动的表征在单分子水平

We demonstrate a method for the synthesis of cyclic polymers and a protocol for characterizing their diffusive motion in a melt state at the single ...

synthesis-cyclic-polymers-characterization-their-diffusive-motion

Nanyang Technological University

Research

JoVE Journal

Chemistry

7.8K 次观看.  King Abdullah University of Science and Technology (KAUST). 一种用于合成和在单分子水平的环状聚合物的扩散运动的表征协议提出。 

视频: Synthesis of Cyclic Polymers and Characterization of Their Diffusive Motion in the Melt State at the Single Molecule Level

Controlled Synthesis and Fluorescence Tracking of Highly Uniform Poly(N-isopropylacrylamide) Microgels

Stimuli-sensitive poly(N-isopropylacrylamide) (PNIPAM) microgels have various prospective practical applications and uses in fundamental research. In this work, we use single particle tracking of fluorescently labeled PNIPAM microgels as a showcase for tuning microgel size by a rapid non-stirred precipitation polymerization procedure. This approach is well suited for prototyping new reaction compositions and conditions or for applications that do not require large amounts of product. Microgel synthesis, particle size and structure determination by dynamic and static light scattering are detailed in the protocol. It is shown that the addition of functional comonomers can have a large influence on the particle nucleation and structure. Single particle tracking by wide-field fluorescence microscopy allows for an investigation of the diffusion of labeled tracer microgels in a concentrated matrix of non-labeled microgels, a system not easily investigated by other methods such as dynamic light scattering.

Controlled Synthesis and Fluorescence Tracking of Highly Uniform PolyN-isopropylacrylamide Microgels

Non-stirred precipitation polymerization provides a rapid, reproducible prototyping approach to the synthesis of stimuli-sensitive poly(N-isopropylacrylamide) microgels of narrow size distribution. In this protocol synthesis, light scattering characterization and single particle fluorescence tracking of these microgels in a wide-field microscopy setup are demonstrated.

可控合成和高度统一聚荧光追踪（<em&gt;ñ</em&gt; -isopropylacrylamide）微凝胶

Stimuli-sensitive poly(N-isopropylacrylamide) (PNIPAM) microgels have various prospective practical applications and uses in fundamental research. In this ...

科研

化学

Self-assembling Morphologies Obtained from Helical Polycarbodiimide Copolymers and Their Triazole Derivatives

A facile method for the preparation of polycarbodiimide-based secondary structures (e.g., nano-rings, &#34;craters,&#34; fibers, looped fibers, fibrous networks, ribbons, worm-like aggregates, toroidal structures, and spherical particles) is described. These aggregates are morphologically influenced by extensive hydrophobic side chain-side chain interactions of the singular polycarbodiimide strands, as inferred by atomic force microscopy (AFM) and scanning electron microscopy (SEM) techniques. Polycarbodiimide-g-polystyrene copolymers (PS-PCDs) were prepared by a combination of synthetic methods, including coordination-insertion polymerization, copper(I)-catalyzed azide alkyne cycloaddition (CuAAC) &#34;click&#34; chemistry, and atom transfer radical polymerization (ATRP). PS-PCDs were found to form specific toroidal architectures at low concentrations in CHCl3. To determine the influence of a more polar solvent medium (i.e., THF and THF/EtOH) on polymer aggregation behavior, a number of representative PS-PCD composites have been tested to show discrete concentration-dependent spherical particles. These fundamental studies are of practical interest to the development of experimental procedures for desirable architectures by directed self-assembly in thin film. These architectures may be exploited as drug carriers, whereas other morphological findings represent certain interest in the area of novel functional materials.

Here, we present a protocol to prepare and visualize secondary structures (e.g., fibers, toroidal architectures, and nano-spheres) derived from helical polycarbodiimides. The morphology characterized by both atomic force microscopy (AFM) and scanning electron microscopy (SEM) was shown to depend on molecular structure, concentration, and the solvent of choice.

从螺旋聚碳化二亚胺共聚物及其三唑衍生物获得自组装形貌

A facile method for the preparation of polycarbodiimide-based secondary structures (e.g., nano-rings, &#34;craters,&#34; fibers, looped fibers, fibrous ...

Synthesis of Terpolymers at Mild Temperatures Using Dynamic Sulfur Bonds in Poly(S-Divinylbenzene)

Elemental sulfur (S8) is a byproduct of the petroleum industry with millions of tons produced annually. Such abundant production and limited applications lead to sulfur as a cost-efficient reagent for polymer synthesis. Inverse vulcanization combines elemental sulfur with a variety of monomers to form functional polysulfides without the need for solvents. Short reaction times and straight forward synthetic methods have led to rapid expansion of inverse vulcanization. However, high reaction temperatures (&#62;160 &#176;C) limit the types of monomers that can be used. Here, the dynamic sulfur bonds in poly(S-divinylbenzene) are used to initiate polymerization at much lower temperatures. The S-S bonds in the prepolymer are less stable than S-S bonds in S8, allowing radical formation at 90 &#176;C rather than 159 &#176;C. A variety of allyl and vinyl ethers have been incorporated to form terpolymers. The resulting materials were characterized by 1H NMR, gel permeation chromatography, and differential scanning calorimetry, as well as examining changes in solubility. This method expands on the solvent-free, thiyl radical chemistry utilized by inverse vulcanization to create polysulfides at mild temperatures. This development broadens the range of monomers that can be incorporated thus expanding the accessible material properties and possible applications.

Synthesis of Terpolymers at Mild Temperatures Using Dynamic Sulfur Bonds in PolyS-Divinylbenzene

The goal of this protocol is to initiate polymerization using dynamic sulfur bonds in poly(S-divinylbenzene) at mild temperatures (90 &#176;C) without using solvents. Terpolymers are characterized by GPC, DSC and 1H NMR, and tested for changes in solubility.

在高温下利用聚苯 (s-二硝基苯) 动态硫键合成三聚体

Elemental sulfur (S8) is a byproduct of the petroleum industry with millions of tons produced annually. Such abundant production and limited applications ...

Synthesis of Monodisperse Cylindrical Nanoparticles via Crystallization-driven Self-assembly of Biodegradable Block Copolymers

The production of monodisperse cylindrical micelles is a significant challenge in polymer chemistry. Most cylindrical constructs formed from diblock copolymers are produced by one of three techniques: thin film rehydration, solvent switching or polymerization-induced self-assembly, and produce only flexible, polydisperse cylinders. Crystallization-driven self-assembly (CDSA) is a method which can produce cylinders with these properties, by stabilizing structures of a lower curvature due to the formation of a crystalline core. However, the living polymerization techniques by which most core-forming blocks are formed are not trivial processes and the CDSA process may yield unsatisfactory results if carried out incorrectly. Here, the synthesis of cylindrical nanoparticles from simple reagents is shown. The drying and purification of reagents prior to a ring-opening polymerization of &#949;-caprolactone catalyzed by diphenyl phosphate is described. This polymer is then chain extended by methyl methacrylate (MMA) followed by N,N-dimethyl acrylamide (DMA) using reversible addition&#8722;fragmentation chain-transfer (RAFT) polymerization, affording a triblock copolymer that can undergo CDSA in ethanol. The living CDSA process is outlined, the results of which yield cylindrical nanoparticles up to 500 nm in length and a length dispersity as low as 1.05. It is anticipated that these protocols will allow others to produce cylindrical nanostructures and elevate the field of CDSA in the future.

Crystallization-driven self-assembly (CDSA) displays the unique ability to fabricate cylindrical nanostructures of narrow length distributions. The organocatalyzed ring-opening polymerization of &#949;-caprolactone and subsequent chain extensions of methyl methacrylate and N,N-dimethyl acrylamide are demonstrated. A living CDSA protocol that produces monodisperse cylinders up to 500 nm in length is outlined.

通过结晶驱动生物降解块共聚物的自组装合成单分散圆柱状纳米粒子

The production of monodisperse cylindrical micelles is a significant challenge in polymer chemistry. Most cylindrical constructs formed from diblock ...

Analyzing Melts and Fluids from Ab Initio Molecular Dynamics Simulations with the UMD Package

We have developed a Python-based open-source package to analyze the results stemming from ab initio molecular-dynamics simulations of fluids. The package is best suited for applications on natural systems, like silicate and oxide melts, water-based fluids, and various supercritical fluids. The package is a collection of Python scripts that include two major libraries dealing with file formats and with crystallography. All the scripts are run at the command line. We propose a simplified format to store the atomic trajectories and relevant thermodynamic information of the simulations, which is saved in UMD files, standing for Universal Molecular Dynamics. The UMD package allows the computation of a series of structural, transport and thermodynamic properties. Starting with the pair-distribution function it defines bond lengths, builds an interatomic connectivity matrix, and eventually determines the chemical speciation. Determining the lifetime of the chemical species allows running a full statistical analysis. Then dedicated scripts compute the mean-square displacements for the atoms as well as for the chemical species. The implemented self-correlation analysis of the atomic velocities yields the diffusion coefficients and the vibrational spectrum. The same analysis applied on the stresses yields the viscosity. The package is available via the GitHub website and via its own dedicated page of the ERC IMPACT project as open-access package.

Melts and fluids are ubiquitous vectors of mass transport in natural systems. We have developed an open-source package to analyze ab initio molecular-dynamics simulations of such systems. We compute structural (bonding, clusterization, chemical speciation), transport (diffusion, viscosity) and thermodynamic properties (vibrational spectrum).

使用 UMD 软件包分析 Ab Initio 分子动力学模拟中的熔体和流体

We have developed a Python-based open-source package to analyze the results stemming from ab initio molecular-dynamics simulations of fluids. The package ...

Designed for Molecular Recycling: A Lignin-Derived Semi-aromatic Biobased Polymer

The development of chemically recyclable biopolymers offers opportunities within the pursuit of a circular economy. Chemically recyclable biopolymers make a positive effort to solve the issue of polymer materials in the disposal phase after the use phase. In this paper, the production of biobased semi-aromatic polyesters, which can be extracted entirely from biomass such as lignin, is described and visualized. The polymer poly-S described in this paper has thermal properties similar to certain commonly used plastics, such as PET. We developed a Green Knoevenagel reaction, which can efficiently produce monomers from aromatic aldehydes and malonic acid. This reaction has been proven to be scalable and has a remarkably low calculated E-factor. These polyesters with ligno-phytochemicals as a starting point show an efficient molecular recycling with minimal losses. The polyester poly(dihydrosinapinic acid) (poly-S) is presented as an example of these semi-aromatic polyesters, and the polymerization, depolymerization, and re-polymerization are described.

An example of a closed-loop approach towards a circular materials economy is described here. A whole sustainable cycle is presented where biobased semi-aromatic polyesters are designed by polymerization, depolymerization, and then re-polymerized with only slight changes in their yields or final properties.

专为分子回收而设计:一种褐宁衍生的半芳烃生物基聚合物

The development of chemically recyclable biopolymers offers opportunities within the pursuit of a circular economy. Chemically recyclable biopolymers make ...

Methods for the Self-integration of Megamolecular Biopolymers on the Drying Air-LC Interface

Living organisms that use water are always prone to drying in the environment. Their activities are driven by biopolymer-based micro- and macro-structures, as seen in the cases of moving water in vascular bundles and moisturizing water in skin layers. In this study, we developed a method for assessing the effect of aqueous liquid crystalline (LC) solutions composed of biopolymers on drying. As LC biopolymers have megamolecular weight, we chose to study polysaccharides, cytoskeletal proteins, and DNA. The observation of biopolymer solutions during drying under polarized light reveals milliscale self-integration starting from the unstable air-LC interface. The dynamics of the aqueous LC biopolymer solutions can be monitored by evaporating water from a one-side-open cell. By analyzing the images taken using cross-polarized light, it is possible to recognize the spatio-temporal changes in the orientational order parameter. This method can be useful for the characterization of not only artificial materials in various fields, but also natural living tissues. We believe that it will provide an evaluation method for soft materials in the biomedical and environmental fields.

A method for the drying-induced self-integration of megamolecular biopolymers on the air-liquid crystalline interface is provided here. This methodology will be useful not only for understanding the macroscopic potentials of biopolymers, but also as an evaluation method for soft materials in biomedical and environmental fields.

对干燥空气-LC接口Megamolecular生物大分子的自我整合方法

Living organisms that use water are always prone to drying in the environment. Their activities are driven by biopolymer-based micro- and ...

生物工程

Depolymerizable Olefinic Polymers Based on Fused-Ring Cyclooctene Monomers

The growing consumption of synthetic polymers and the accumulation of polymer waste have led to a pressing need for new routes to sustainable materials. Achieving a closed-loop polymer economy via chemical recycling to monomer (CRM) is one such promising route. Our group recently reported a new CRM system based on polymers prepared by ring-opening metathesis polymerization (ROMP) of trans-cyclobutane fused cyclooctene (tCBCO) monomers. This system offers several key advantages, including the ease of polymerization at ambient temperatures, quantitative depolymerization to monomers under mild conditions, and a broad range of functionalities and thermomechanical properties. Here, we outline detailed protocols for the preparation of tCBCO-based monomers and their corresponding polymers, including the preparation of elastic polymer networks and compression molding of linear thermoplastic polymers. We also outline the preparation of high ring strain E-alkene tCBCO monomers and their living polymerization. Finally, the procedures for the depolymerization of linear polymers and polymer networks are also demonstrated.

Here, we describe protocols for the preparation of trans-cyclobutane fused cyclooctenes (tCBCO),&#160;their polymerization to prepare depolymerizable olefinic polymers, and the depolymerization of these polymers under mild conditions. Additionally, protocols for the preparation of depolymerizable networks and compression molding of rigid linear plastics based on this system are described.

基于熔环环辛烯单体的可解聚烯烃聚合物

The growing consumption of synthetic polymers and the accumulation of polymer waste have led to a pressing need for new routes to sustainable materials. ...

Polymerization

Source: Vy M. Dong and Jan Riedel, Department of Chemistry, University of California, Irvine, CA
Polymers are made from macromolecules, which are composed of repeating units (the so called monomeric units). In our modern world, polymers play an important role. One of the first important polymers was nylon, which is a polyamide. It found widespread application in tooth brushes and stockings.

Polymerization: Types of Polymerizations and Applications

聚合

Source: Vy M. Dong and Jan Riedel, Department of Chemistry, University of California, Irvine, CA
Polymers are made from macromolecules, which are composed ...

教育

JoVE Science Education

有机化学 (2)

Kinetics of Addition Polymerization to Polydimethylsiloxane

Source: <a href="https://www.jove.com/author/Kerry+M._Dooley">Kerry M. Dooley</a> and Michael G. Benton, Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA
Polymers are molecules consisting of many repeating monomer units that are chemically bonded into long chains. They exhibit a broad range of physical properties, which are affected by their chemical structure, molecular weight and degree of polymerization. The polymer industry manufactures thousands of raw materials used in a broad variety of commercial products.1,2
The goal of this video is to perform an addition polymerization reaction and then evaluate the resulting product to understand how viscosity can be used to determine polymer molecular weight. Additionally, this experiment will investigate how molecular weight can be related to monomer conversion.

Synthesis of Polydimethylsiloxane via Addition Polymerization

烷的加入聚合动力学

Source: Kerry M. Dooley and Michael G. Benton, Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA
Polymers are molecules ...