The Deutsche Forschungsgemeinschaft (DFG) is acknowledged for financial support within the Sonderforschungsbereich SFB 985 "Functional Microgels and Microgel Systems".

1.微凝胶合成注:N -isopropylacrylamide（NIPAM）从正己烷重结晶。原样使用其它试剂。 <ol><li>聚（NIPAM）矩阵微凝胶的常规合成批<ol><li>在过滤245毫升溶解1.8克NIPAM和24毫克N，N&#39;-bisacrylamide（BIS）（0.2微米的再生纤维素（RC）的膜过滤器）在装有回流冷凝器的500毫升三颈圆底烧瓶中双蒸水，搅拌器和橡胶隔片。 </li><li>插入温度计和120mm的针头穿过隔膜的氮气输入。 </li><li>加热该溶液至60℃，同时搅拌。通过用氮气吹扫40分钟脱氧溶液。 </li><li>同时准备155毫克过硫酸钾（KPS）的在过滤双蒸水和气泡用氮气将溶液以除去氧气加入5ml引发剂溶液。 </li><li>转让完成5毫升KPS小号olution在装有120mm的针氮气洗涤注射器。 </li><li>解除在三颈烧瓶中的溶液水平以上的氮针和迅速通过橡胶隔膜加入KPS溶液到反应器中。 </li><li>让聚合继续进行，在氮气流和缓慢搅拌1小时，在60℃。 </li><li>使用布氏漏斗和滤纸向热的反应溶液，以丢弃大的聚集体进行过滤。让分散体冷却下来。 </li><li>离心机和再分散的分散体40分钟三次在257,000 xg离心，最后再分散在双蒸水的最小可行量的沉淀物。通常，这是2-4毫升。 </li><li>冻干该分散存储。 </li></ol></li><li>荧光标记的聚（NIPAM）微凝胶的非搅拌合成<ol><li>在玻璃容器称量257.7毫克NIPAM，3.5毫克BIS和1.5毫克丙烯酰氧乙基硫代罗丹明B（染料），并加入10毫升的过滤双重蒸馏的编辑水。 </li><li> Ultrasonicate 15分钟的染料单体溶液以溶解染料在水中。 </li><li>制备不含染料的相同溶液到一个单独的玻璃容器中。 </li><li>制备与使用不含染料的单体溶液以获得具有各种染料浓度的浓度系列中的染料单体溶液的各种稀释液。在这项工作中，使用的染料在0.02-0.1毫摩尔/ L的浓度范围。 </li><li>溶解在10毫升过滤的双蒸水8.4毫克KPS以得到引发剂溶液。 </li><li>传送将0.5ml浓度系列和0.5ml的KPS溶液与直径为10毫米到试管以获得最终的反应溶液并用橡胶隔片密封。 </li><li>在连接到一个加热循环，以63℃的双层壁玻璃容器预热油浴中。 </li><li>通过120毫米针用氮气吹扫20分钟去氧反应液。 </li><li>将管放入自动对焦loating平台和浸入平台放入预热油浴。设定温度至60℃。在浴最初更高的温度是必要的，因为室温溶液冷却浴。用于高精密粒径调谐初始反应过程中的温度控制已成为严格，一般为±0.1℃。 </li><li>让反应继续进行适当的时间。通常1小时就足够了。 </li><li>迅速转移反应管至烘箱中在60℃，并把热分散一滴至10ml过滤预热过PNIPAM体积相转变温度（VPTT，32 -34℃）1双蒸水，为DLS表征在折叠状态。 </li><li>让分散体的其余部分冷却到室温，并将其转移到离心管中。 </li><li>对溶液离心40分钟三次在257,000 XG，最后稀释微凝胶在2毫升过滤的双蒸水FOr用作为示踪粒子。 </li></ol></li></ol> 2.光散射特性<ol><li>流体动力学半径测定折叠状态，通过动态光散射<ol><li>洗试管并用丙酮蒸气玻璃器皿。 </li><li>热的10ml过滤（ 例如，200纳米或更小的RC滤波器）双蒸水通过PNIPAM VPTT。 </li><li>使用预先加热的针（0.9×40毫米），注射器（1毫升）转移热分散的液滴向过滤水。 </li><li>脾气DLS测角仪指数匹配浴至50℃，不让它冷却下来的样品转移到仪器上。 </li><li>找到最大的散射角，其中的散射强度足以获得通过进行试验测量一相关图。 <ol><li>插入样品试管（10毫米直径的玻璃管用1ml颗粒分散体的）。移动至检测器臂到小散射角（这里30°）。 </li><li>检查FO光束轮廓r多个散射:主光束，没有多重散射等周围没有辉光检查计数范围是适于在最低散射角度测量（约30和600千赫之间;软件窗口的右上角。） </li><li>移动测角仪手臂最高的散射角（在这里选择120°）。检查计数率依然为测量足够高（30和600千赫之间）。如果强度过低，移动手臂以降低散射角。 </li></ol></li><li>检查光束通过直观的甲苯浴玻璃在最低的散射角，如果入射光束灼热周围观察到多重散射发生。在这种情况下，降低了激光强度或使用更高的稀释。 </li><li>获得的最小和最大散射角20之间相关图（ 例如 ，30° - 140°）用60秒的最小采集时间。增加了采集时间为弱强度大散射角如果必要的。 </li></ol></li><li>数据分析37 <ol><li>计算散射向量量值为按散射角<img alt="公式2" src="/files/ftp_upload/54419/54419eq2.jpg" /> ，其中n是分散体的折射率， <img alt="（3）式" src="/files/ftp_upload/54419/54419eq3.jpg" />在真空中激光的波长和<img alt="4式" src="/files/ftp_upload/54419/54419eq4.jpg" />散射角。 </li><li>在这种情况下测量软件提供了强关联函数<img alt="式5" src="/files/ftp_upload/54419/54419eq5.jpg" /> ，将其转换为电场相关函数<img alt="6式" src="/files/ftp_upload/54419/54419eq6.jpg" />根据<img alt="7式" src="/files/ftp_upload/54419/54419eq7.jpg" /> 。参数<img alt="8式" src="/files/ftp_upload/54419/54419eq8.jpg" />是关系到散射光奥雅纳的空间相干程度的无趣工具参数r是探测器面积。 </li><li>上相关图进行累积量分析， 即 ，适合二阶多项式的每个电场相关函数的对数<img alt="9式" src="/files/ftp_upload/54419/54419eq9.jpg" />通过线性最小二乘。 <img alt="8式" src="/files/ftp_upload/54419/54419eq8.jpg" />显示为拟合的截距和其精确值是不重要的在相对于数据分析。限制拟合 ​​到一个有意义的延迟时间τ 的值， 例如 ，这样的相关性幅度10 -最大振幅的20％。第一阶项的系数是相关函数的平均衰减速度， <img alt="10式" src="/files/ftp_upload/54419/54419eq10.jpg" /> 。 </li><li>找到的均值扩散系数的最可能的值<img alt="11式" src="/files/ftp_upload/54419/54419eq11.jpg" />通过线性最小二乘颗粒适合在<img alt="12式" src="/files/ftp_upload/54419/54419eq12.jpg" /> 。如果<img alt="10式" src="/files/ftp_upload/54419/54419eq10.jpg" />反对<img alt="13式" src="/files/ftp_upload/54419/54419eq13.jpg" />不出现的线性和经过误差范围内的原点，粒度分布宽和流体力学半径将被定义不佳。 </li><li>从斯托克斯 - 爱因斯坦关系计算平均流体动力学半径<img alt="14式" src="/files/ftp_upload/54419/54419eq14.jpg" /> ，其中<img alt="15式" src="/files/ftp_upload/54419/54419eq15.jpg" />是波尔兹曼系数， <img alt="16式" src="/files/ftp_upload/54419/54419eq16.jpg" />绝对温度和<img alt="17式" src="/files/ftp_upload/54419/54419eq17.jpg" />该分散体在粘度<img alt="16式" src="/files/ftp_upload/54419/54419eq16.jpg" /> 。传播的标准偏差<img alt="11式" src="/files/ftp_upload/54419/54419eq11.jpg" />至<img alt="18式" src="/files/ftp_upload/54419/54419eq18.jpg" /> 。 </l我&gt; </ol></li><li>颗粒结构测定静态光散射<ol><li>洗试管并用丙酮蒸气玻璃器皿。使用直径为20毫米或更大的比色杯，以尽量减少柱面透镜效果。 </li><li>过滤器（200纳米RC滤波器或更小）大约20毫升双蒸水至玻璃小瓶中，并纯化分散一滴转移到小瓶中。使用它进行样品制备，除去从制造工艺残留的杂质之前洗涤用10毫升水的过滤器。 </li><li>检查样品反对任何环境光源。如果观察到蓝色色调，样品很可能是过于浓缩。相应地稀释。 </li><li>用过滤后的水多次冲洗试管准备背景水样品，然后填充到合适的样品体积，这取决于反应杯，并在仪器中的激光的位置。激光必须穿过样品而不从弯液面被折射。 </li><li>校准仪器和设备耳鼻喉科用甲苯样本。 </li><li>测量整个可用的角度范围散水（背景）。 </li><li>测量从整个可用的角度范围的样品的散射强度优选在几个波长。归到正向散射强度的散射图案被称为形状因子。 </li><li>如果颗粒结构是已知的，使用适当的模型公式计算在不同波长测量数据集全球契合。 </li><li>为正则直接（如FitIt！33）未知颗粒结构使用或更一般的间接傅立叶逆变换21,22例程在结合一对距离分布函数（仅对于球形粒子）的解卷积23,24为粒子的近似分类类型。 </li><li>万一嵌合或反转例程提供粒子半径分布函数的估计，计算多分散性指数（通过其平均值除以分布的标准偏差）。 </li></ol></li></ol> 3.粒子跟踪由宽视场荧光显微镜注:在20℃的465±7 nm和405±7nm的水力半径示踪和基质颗粒，分别用于颗粒跟踪。 <ol><li>样品制备<ol><li>通过再分散冻干未标记微粒凝胶的已知量的双蒸水已知量制备浓缩基质微粒凝胶分散体。加标记的示踪粒子的小体积。 </li><li>在确认显微镜适当的示踪剂微凝胶浓度。最佳浓度是磁道最大数量的同时采集之间的折衷，同时具有示踪剂浓度足够低，使得该示踪粒子轨迹在采集过程中交叉的概率是可忽略的。 </li><li>准备通过蒸发浓缩分散液水在烘箱。通过蒸发之前分散体的重量比较样品的原始重量确定的重量浓度。 </li></ol></li><li>数据采集​​与分析<ol><li>使用所需的放大倍率的适当物镜和光圈为示踪剂的激发和荧光同时从收集样品。在这项工作中，使用100X / 1.3 NA油浸物镜。 </li><li>湿度室放置到一个XYZ-压电表，适合商用的显微镜​​。 </li><li>为了防止干燥样品，将等离子清洗盖玻片成所需浓度的保湿室和吸管10微升聚（NIPAM）的分散到滑。 </li><li>根据荧光染料的激发和发射光谱，使用合适的激光激发和适当地调整激光功率。的强度应足够低，以避免染料的快速光漂白，但在同时足够强的精确的单粒子定位（见下文）。在这项工作中，使用561纳米的二极管泵浦固体激光器，并保持激光功率恒定在16毫瓦（ 约 0.5千瓦厘米-2的样品）进行所有的测量。 </li><li>为了获得均匀的样品照明，使用这里描述的临界照明设置。为此，耦合激光器到多模光纤（NA 0.22±0.02为0.6mm纤芯直径），摇使用涡旋纤维以时间平均出来的激光斑点，并投射在纤维端插入样品平面。 </li><li>校准从盖玻片的背面反射的Z距离和通过移动物镜略微向上集中几微米到样品和使用的z补偿器固定的z位置。这避免了因盖玻片的界面效果。 </li><li>调整检测器的参数，如曝光时间，对荧光信号的强度。在这种情况下，使用相机EMCCD用0.1秒的曝光时间，电子倍增模式和50的增益。 </li><li>获得几部电影有帧的适当数量，以获得足够的滞后时间来计算在样品的不同区域中的微凝胶的均方位移。在这项工作中，使用500或1000帧采集帧数。 </li><li>通过使用高斯拟合25每帧中的粒子的定位数据进行分析，并使用恰当的粒子追踪算法26以获得均方位移。27计算通过平均在所有的电影所有曲目平均值和标准偏差。通过线性回归计算滞后时间长的扩散系数<img alt="19式" src="/files/ftp_upload/54419/54419eq19.jpg" /> ，其中<img alt="20式" src="/files/ftp_upload/54419/54419eq20.jpg" />是均方位移，D的平均扩散系数和τ的延迟时间。 </li><li>美东时间从反常扩散方程imate异常参数γ <img alt="21式" src="/files/ftp_upload/54419/54419eq21.jpg" />通过转换数据以对数标度，得到<img alt="22式" src="/files/ftp_upload/54419/54419eq22.jpg" /> 。这种异常的参数<img alt="23式" src="/files/ftp_upload/54419/54419eq23.jpg" />通过剧情的衍生给出。该衍生物可以通过数据点的有限差来估计，或者通过多项式函数拟合数据点和分析鉴别。通过绘制拟合残差和剩余范增加多项式阶决定了足够程度的多项式拟合函数。 </li><li>重复同样的步骤对不同浓度的微粒凝胶基质。 </li></ol></li></ol>

<ol>
	<li>Pelton, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Temperature-sensitive+aqueous+microgels.">Temperature-sensitive aqueous microgels.</a> Adv. Colloid Interfac. 85, 1-33 (2000).</li><li>Pich, A., Richtering, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microgels+by+Precipitation+Polymerization:+Synthesis,+Characterization+and+Functionalization.">Microgels by Precipitation Polymerization: Synthesis, Characterization and Functionalization.</a> Adv. Polym. Sci. 234, 1-37 (2010).</li><li>Richtering, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Responsive+Emulsions+Stabilized+by+Stimuli-Sensitive+Microgels:+Emulsions+with+Special+Non-Pickering+Properties.">Responsive Emulsions Stabilized by Stimuli-Sensitive Microgels: Emulsions with Special Non-Pickering Properties.</a> Langmuir. 28 (50), 17218-17229 (2012).</li><li>Wiese, S., Spiess, A. C., Richtering, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microgel-Stabilized+Smart+Emulsions+for+Biocatalysis.">Microgel-Stabilized Smart Emulsions for Biocatalysis.</a> Angew. Chem. Int. Edit. 52 (2), 576-579 (2012).</li><li>Schmitt, V., Ravaine, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Surface+compaction+versus+stretching+in+Pickering+emulsions+stabilised+by+microgels.">Surface compaction versus stretching in Pickering emulsions stabilised by microgels.</a> Curr. Opin. Colloid In. 18 (6), 532-541 (2013).</li><li>Wellert, S., Richter, M., Hellweg, T., von Klitzing, ., R, Y., Hertle, <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Responsive+Microgels+at+Surfaces+and+Interfaces.">Responsive Microgels at Surfaces and Interfaces.</a> Z. Phys. Chem. 229 (7-8), 1-26 (2015).</li><li>Li, Z., Harbottle, D., Pensini, E., Ngai, T., Richtering, W., Xu, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fundamental+Study+of+Emulsions+Stabilized+by+Soft+and+Rigid+Particles.">Fundamental Study of Emulsions Stabilized by Soft and Rigid Particles.</a> Langmuir. 31 (23), 6282-6288 (2015).</li><li>Deshmukh, O. S., van den Ende, D., Stuart, M. C., Mugele, F., Duits, M. H. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hard+and+soft+colloids+at+fluid+interfaces:+Adsorption,+interactions,+assembly+&amp;+rheology.">Hard and soft colloids at fluid interfaces: Adsorption, interactions, assembly &amp; rheology.</a> Adv. Colloid Interfac. 222, 215-227 (2015).</li><li>Serpe, M. J., Kim, J., Lyon, L. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Colloidal+Hydrogel+Microlenses.">Colloidal Hydrogel Microlenses.</a> Adv. Mater. 16 (2), 184-187 (2004).</li><li>Schmidt, S., Zeiser, M., Hellweg, T., Duschl, C., Fery, A., M&#246;hwald, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adhesion+and+Mechanical+Properties+of+PNIPAM+Microgel+Films+and+Their+Potential+Use+as+Switchable+Cell+Culture+Substrates.">Adhesion and Mechanical Properties of PNIPAM Microgel Films and Their Potential Use as Switchable Cell Culture Substrates.</a> Adv. Func. Mater. 20 (19), 3235-3243 (2010).</li><li>Xia, Y., He, X., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Thermoresponsive+Microgel+Films+for+Harvesting+Cells+and+Cell+Sheets.">Thermoresponsive Microgel Films for Harvesting Cells and Cell Sheets.</a> Biomacromolecules. 14 (10), 3615-3625 (2013).</li><li>Guan, Y., Zhang, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=PNIPAM+microgels+for+biomedical+applications:+from+dispersed+particles+to+3D+assemblies.">PNIPAM microgels for biomedical applications: from dispersed particles to 3D assemblies.</a> Soft Matter. 7 (14), 6375 (2011).</li><li>Yunker, P. J., Chen, K., Gratale, M. D., Lohr, M. A., Still, T., Yodh, A. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Physics+in+ordered+and+disordered+colloidal+matter+composed+of+poly(N-isopropylacrylamide)+microgel+particles.">Physics in ordered and disordered colloidal matter composed of poly(N-isopropylacrylamide) microgel particles.</a> Rep. Prog. Phys. 77 (5), 056601-056629 (2014).</li><li>Lohr, M. A., Still, T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Vibrational+and+structural+signatures+of+the+crossover+between+dense+glassy+and+sparse+gel-like+attractive+colloidal+packings.">Vibrational and structural signatures of the crossover between dense glassy and sparse gel-like attractive colloidal packings.</a> Phys. Rev. E. 90 (6), 062305 (2014).</li><li>Dreyfus, R., Xu, Y., Still, T., Hough, L. A., Yodh, A. G., Torquato, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Diagnosing+hyperuniformity+in+two-dimensional,+disordered,+jammed+packings+of+soft+spheres.">Diagnosing hyperuniformity in two-dimensional, disordered, jammed packings of soft spheres.</a> Phys. Rev. E. 91 (1), 012302-012312 (2015).</li><li>Kojima, H., Tanaka, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reentrant+volume+phase+transition+of+cross-linked+poly(N-isopropylacrylamide)+gels+in+mixed+solvents+of+water/methanol.">Reentrant volume phase transition of cross-linked poly(N-isopropylacrylamide) gels in mixed solvents of water/methanol.</a> Soft Matter. 8 (10), 3010-3011 (2012).</li><li>Hofmann, C. H., Plamper, F. A., Scherzinger, C., Hietala, S., Richtering, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cononsolvency+Revisited:+Solvent+Entrapment+by+N-Isopropylacrylamide+and+N,+N-Diethylacrylamide+Microgels+in+Different+Water/Methanol+Mixtures.">Cononsolvency Revisited: Solvent Entrapment by N-Isopropylacrylamide and N, N-Diethylacrylamide Microgels in Different Water/Methanol Mixtures.</a> Macromolecules. 46 (2), 523-532 (2013).</li><li>Bischofberger, I., Calzolari, D. C. E., Trappe, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Co-nonsolvency+of+PNiPAM+at+the+transition+between+solvation+mechanisms.">Co-nonsolvency of PNiPAM at the transition between solvation mechanisms.</a> Soft Matter. 10 (41), 8288-8295 (2014).</li><li>Virtanen, O. L. J., Richtering, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Kinetics+and+particle+size+control+in+non-stirred+precipitation+polymerization+of+N-isopropylacrylamide.">Kinetics and particle size control in non-stirred precipitation polymerization of N-isopropylacrylamide.</a> Colloid Polym. Sci. 292 (8), 1743-1756 (2014).</li><li>Virtanen, O. L. J., Ala-Mutka, H. M., Richtering, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Can+the+Reaction+Mechanism+of+Radical+Solution+Polymerization+Explain+the+Microgel+Final+Particle+Volume+in+Precipitation+Polymerization+of+N-Isopropylacrylamide?.">Can the Reaction Mechanism of Radical Solution Polymerization Explain the Microgel Final Particle Volume in Precipitation Polymerization of N-Isopropylacrylamide?.</a> Macromol. Chem. Phys. 216 (13), 1431-1440 (2015).</li><li>Glatter, O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+new+method+for+the+evaluation+of+small-angle+scattering+data.">A new method for the evaluation of small-angle scattering data.</a> J. Appl. Crystallogr. 10 (5), 415-421 (1977).</li><li>Svergun, D. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Determination+of+the+regularization+parameter+in+indirect-transform+methods+using+perceptual+criteria.">Determination of the regularization parameter in indirect-transform methods using perceptual criteria.</a> J. Appl. Crystallogr. 25 (4), 495-503 (1992).</li><li>Glatter, O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Convolution+Square+Root+of+Band-Limited+Symmetrical+Functions+and+Its+Application+to+Small-Angle+Scattering+Data.">Convolution Square Root of Band-Limited Symmetrical Functions and Its Application to Small-Angle Scattering Data.</a> J. Appl. Crystallogr. 14, 101-108 (1981).</li><li>Glatter, O., Hainisch, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Improvements+in+Real-Space+Deconvolution+of+Small-Angle+Scattering+Data.">Improvements in Real-Space Deconvolution of Small-Angle Scattering Data.</a> J. Appl. Crystallogr. 17, 435-441 (1984).</li><li>Cheezum, M. K., Walker, W. F., Guilford, W. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantitative+Comparison+of+Algorithms+for+Tracking+Single+Fluorescent+Particles.">Quantitative Comparison of Algorithms for Tracking Single Fluorescent Particles.</a> Biophys. J. 81 (4), 2378-2388 (2001).</li><li>W&#246;ll, D., K&#246;lbl, C., Stempfle, B., Karrenbauer, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+novel+method+for+automatic+single+molecule+tracking+of+blinking+molecules+at+low+intensities.">A novel method for automatic single molecule tracking of blinking molecules at low intensities.</a> Phys. Chem. Chem. Phys. 15 (17), 6196-6205 (2013).</li><li>Saxton, M. J., Jacobson, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Single-particle+tracking:+Applications+to+membrane+dynamics.">Single-particle tracking: Applications to membrane dynamics.</a> Annu. Rev. Bioph. Biom. 26, 373-399 (1997).</li><li>Pusey, P. N., van Megen, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Detection+of+small+polydispersities+by+photon+correlation+spectroscopy.">Detection of small polydispersities by photon correlation spectroscopy.</a> J. Chem. Phys. 80 (8), 3513 (1984).</li><li>Stieger, M., Pedersen, J. S., Richtering, W., Lindner, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Small-angle+neutron+scattering+study+of+structural+changes+in+temperature+sensitive+microgel+colloids.">Small-angle neutron scattering study of structural changes in temperature sensitive microgel colloids.</a> J. Chem. Phys. 120 (13), 6197-6206 (2004).</li><li>Wu, X., Pelton, R. H., Hamielec, A. E., Woods, D. R., McPhee, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+kinetics+of+poly(N-isopropylacrylamide)+microgel+latex+formation.">The kinetics of poly(N-isopropylacrylamide) microgel latex formation.</a> Colloid Polym. Sci. 272, 467-477 (1994).</li><li>Weeks, E. R., Weitz, D. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Subdiffusion+and+the+cage+effect+studied+near+the+colloidal+glass+transition.">Subdiffusion and the cage effect studied near the colloidal glass transition.</a> Chem. Phys. 284 (1-2), 361-367 (2002).</li><li>Ernst, D., K&#246;hler, J., Weiss, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Probing+the+type+of+anomalous+diffusion+with+single-particle+tracking.">Probing the type of anomalous diffusion with single-particle tracking.</a> Phys. Chem. Chem. Phys. 16 (17), 7686-7691 (2014).</li><li>. FitIt! (Version 1.1.4) Available from: <a target="_blank" href="https://www.github.com/ovirtanen/fitit">https://www.github.com/ovirtanen/fitit</a> (2015)</li><li>Provencher, S. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Constrained+Regularization+Method+For+Inverting+Data+Represented+By+A+Linear+Algebraic+or+Integral+Equations.">A Constrained Regularization Method For Inverting Data Represented By A Linear Algebraic or Integral Equations.</a> Comput. Phys. Commun. 27 (3), 213-227 (1982).</li><li>Holtzer, L., Meckel, T., 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=Nanometric+three-dimensional+tracking+of+individual+quantum+dots+in+cells.">Nanometric three-dimensional tracking of individual quantum dots in cells.</a> Appl. Phys. Lett. 90 (5), 053902-053904 (2007).</li><li>Diezmann, A. V., Lee, M. Y., Lew, M. D., Moerner, W. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Correcting+field-dependent+aberrations+with+nanoscale+accuracy+in+three-dimensional+single-molecule+localization+microscopy.">Correcting field-dependent aberrations with nanoscale accuracy in three-dimensional single-molecule localization microscopy.</a> Optica. 2 (11), 985-989 (2015).</li><li>Lindner, P., Zemb, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Neutrons, X-rays and Light: Scattering Methods Applied to Soft Condensed Matter. , (2002).</li></ol>

The authors have nothing to disclose.

少量官能共聚单体的加成可对PNIPAM衍生微凝胶的粒度和结构的显著效果。同时小规模试管聚合是考虑到这种变化的好方法，有助于迅速找到目标粒度合适的反应剂组合物根据需要扩大该反应。该颗粒的质量是约指数依赖当热分解引发剂的聚合温度，例如KPS，使用20，因此，人们需要建立反应器中良好的再现内稳定和精确的温度控制。从常规的分批反应和非搅拌的反应最终颗粒体积通常是良好的一致性，如果一个最小化批次合成有关的扰动，如反应混合物的太剧烈搅拌以EV烯出温度梯度在大型反应器中，或使用的引发剂溶液过量，使得在起始期间，反应温度的变化。 动态光散射是一种行之有效的和快速的方法来确定的大量原位颗粒的扩散行为。这是必不可少的但收购在多个散射角的数据。在任意一个角DLS测定法，具有形状因数最小或在宽的尺寸分布的情况下一致，将导致表观扩散系数从样品的平均扩散系数显著不同。这种情况下，可以从非线性行为在Γ2被识别与Q 2的情节。用于解决宽或多峰粒度分布，可以尝试使用逆拉普拉斯变换算法如CONTIN 34。 DLS然而，不适合用于这一目的由于病态NAT反演问题URE。 对于动态和静态光散射样品必须充分稀释以避免多重散射，其无效常规数据分析。用于通过SLS外形确定也颗粒和溶剂的折射率差必须以避免米氏散射，从而防止直接的形式因子分析低。这个条件被满足时， <img alt="30式" src="/files/ftp_upload/54419/54419eq30.jpg" /> ，其中<img alt="31式" src="/files/ftp_upload/54419/54419eq31.jpg" />是平均颗粒半径和<img alt="32式" src="/files/ftp_upload/54419/54419eq32.jpg" />的溶剂和颗粒的折射率之间的差。为微凝胶与溶剂广泛肿此准则被满足的，但在一般的粒子必须对比度以足够高的折射​​率溶剂匹配。米氏散射可以从T的涂抹被识别他形成因子最小值，效果，当折射率差减小而减弱。 光散射方法提供整体平均的信息，而宽视野粒子跟踪可用于研究在实空间单粒子的扩散行为。在对比的基础上的光散射粒子追踪，荧光的高灵敏度允许小颗粒的跟踪，并在极端情况下，即使单个分子。此外，标记的和未标记的颗粒的比例可以适于精确也测量在高度浓缩溶液。因此粒子跟踪提供免费模型的方法来确定在原位胶体甚至允许单个颗粒的行为之间的比较的扩散系数和扩散模式。单示踪剂的定位精度通常比衍射极限更好，但依赖于荧光Si的信号 - 噪声比在宽视场设置单粒子gnal。因此，利用表现出一个高量子产率，良好的光稳定性和最大吸收附近的激发波长的染料标记为良好的效果的先决条件。示踪剂浓度，以便尽量减少不同颗粒扰乱跟踪算法的轨迹的交叉保持较低。对于浓缩的分散体，荧光示踪剂的浓度可以通过标记和非标记颗粒混合来调节。上的点扩散函数工程最近的工作使三维粒子跟踪35,36，其可用于研究在不同的空间方向上的各向异性扩散。 综上所述，准确表征DLS和小型试管聚合为最终微凝胶颗粒体积的高精度微调健壮的框架。光散射和荧光粒子跟踪技术提供的合奏补充信息和在广泛分散的浓度范围内单粒子扩散行为。并有可能定义良好的软质颗粒的合成来跟踪他们在不同浓度的溶液的组合将是显著重要性软粒子系统动力学的研究和充分研究的硬胶体系统的比较。

刺激敏感聚（N -isopropylacrylamide）（PNIPAM）微凝胶1,2吸引过去二十年的不断兴趣，因为他们在各种智能应用的潜力。证明用例包括可切换的乳液稳定剂3-8，微透镜9中，为了便于细胞收集10,11细胞培养基材，以及低分子量化合物的智能的载体和其它生物医学用途12。从一个基础研究点这些颗粒已被证明是调查受试者有用诸如胶体相互作用13-15和聚合物-溶剂相互作用16-18。 成功使用PNIPAM微凝胶以及它们的衍生物中的任何给定的应用的典型地需要在粒度分布的平均粒径和宽的知识。对实验结果的涉及PNIPAM微正确解释凝胶，颗粒结构，这可以通过官能共聚单体的影响，必须已知。动态和静态光散射（DLS和SLS，分别）是唯一适用于因为这些方法是快速和相对容易使用的获取这些信息;它们探查颗粒性能非侵入在其天然环境中（分散液）。 DLS和SLS还收集广大避免由于样本量小，是典型的显微镜方法而产生的偏见颗粒的数据。因此，这项工作的第一目的是介绍关于对从业人员新的胶体特性的光散射很好的做法。 典型地，沉淀聚合在实验室规模进行，并找到合适的反应条件对于特定的颗粒属性可以是费力的和所需要的合成的许多重复。在对比大批量合成，无搅拌沉淀聚合19,20是芳APID程序，其中不同的反应物组合物的批次可以聚合粒径分布窄的同时屈服颗粒。同时聚合减少实验误差，产量大意味着正确的反应条件可快扩大该反应被发现。因此，我们的第二个目的是要证明在原型和在不需要大量产品的应用程序的非搅拌沉淀聚合的有用性。 合成与表征的不同方面走到了一起，在胶体相互作用的研究荧光标记的PNIPAM微凝胶的应用实例。这里我们使用高度精确的单粒子跟踪调查标记的示踪剂微凝胶在未标记的基质微凝胶分散在很宽的基质浓度范围扩散和解决集中胶体分散的笼效应。宽视场荧光显微镜是非常适合FOR此​​目的，因为它可以表征中的大量潜在的不同的矩阵种类的几示踪分子的特定行为。这是相对于技术如DLS，SLS和流变学，其测量的系统总体平均性能，因此无法解析在一个大系统的小数目的探针粒子的行为。此外，在该具体例常规的光散射方法不能也利用由于高粒子浓度，这会导致强烈的多次散射无效任何标准分析。自动数据处理和统计方法使用使整个系统的行为也对单粒子跟踪，当通过大样本平均分析。

<table border="0" cellpadding="0" cellspacing="0" width="741">
	<tbody>
		<tr height="20">
			<td height="20" style="height:20px;width:259px;">Acetone</td>
			<td style="width:199px;">VWR Chemicals</td>
			<td style="width:155px;">KRAF13455</td>
			<td style="width:129px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:259px;">Bisacrylamid</td>
			<td style="width:199px;">AppliChem</td>
			<td style="width:155px;">A3636</td>
			<td style="width:129px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:259px;">n-Hexane</td>
			<td style="width:199px;">Merck</td>
			<td style="width:155px;">104374</td>
			<td style="width:129px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:259px;">N-Isopropylacrylamide</td>
			<td style="width:199px;">Fisher Scientific</td>
			<td style="width:155px;">AC412785000</td>
			<td>recrystallized from n-hexane</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:259px;">Methacryloxyethyl thiocarbamoyl rhodamine B</td>
			<td style="width:199px;">Polysciences</td>
			<td style="width:155px;">23591</td>
			<td style="width:129px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:259px;">Potassium peroxodisulfate</td>
			<td style="width:199px;">Merck</td>
			<td style="width:155px;">105091</td>
			<td style="width:129px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:259px;">Silicone oil 47 V 350</td>
			<td style="width:199px;">VWR Chemicals</td>
			<td style="width:155px;">83851</td>
			<td style="width:129px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:259px;">Toluene</td>
			<td style="width:199px;">Sigma Aldrich</td>
			<td style="width:155px;">244511</td>
			<td style="width:129px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">F12 Refrigerated/heating circulator</td>
			<td style="width:199px;">Julabo</td>
			<td>9116612</td>
			<td style="width:129px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Microscope</td>
			<td>Olympus</td>
			<td>IX83</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">XY(Z) Piezo System</td>
			<td>Physik Instrumente</td>
			<td>P-545.3R7</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">100x Oil immersion objective</td>
			<td>Olympus</td>
			<td>UPLSAPO</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">QuadLine Beamsplitter</td>
			<td>AHF Analysentechnik</td>
			<td>F68-556T</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">&#160;Cobolt Jive 150 laser</td>
			<td>Cobolt</td>
			<td>0561-04-01-0150-300</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Multimode Fiber</td>
			<td>Thorlabs</td>
			<td>UM22-600</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">iXON Ultra 897 EMCCD camera</td>
			<td>Andor</td>
			<td>DU-897U-CS0-BV</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Laser goniometer</td>
			<td>SLS Systemtechnik</td>
			<td>Mark III</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">CF40 Cryo-compact circulator</td>
			<td>Julabo</td>
			<td>9400340</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Laser goniometer system&#160;</td>
			<td>ALV GmbH</td>
			<td>ALV / CGS-8F</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Multi-tau corretator</td>
			<td>ALV GmbH</td>
			<td>ALV-7004</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Light scattering electronics</td>
			<td>ALV GmbH</td>
			<td>ALV / LSE 5004</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Photon counting module</td>
			<td>PerkinElmer</td>
			<td>SPCM-CD2969</td>
			<td>2 units in pseudo cross-correlation mode</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">633 nm HeNe Laser</td>
			<td>JDS Uniphase</td>
			<td>1145P</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">F32 Refrigerated/heating circulator</td>
			<td>Julabo</td>
			<td>9312632</td>
			<td></td>
		</tr>
	</tbody>
</table>

controlled synthesis and fluorescence tracking of highly uniform poly(n-isopropylacrylamide) microgels

刺激敏感聚（N -isopropylacrylamide）（PNIPAM）微凝胶具有前瞻性的各种实际应用和基础研究使用。在这项工作中，我们使用单一粒子由一个快速无搅拌沉淀聚合过程跟踪的荧光标记PNIPAM微凝胶作为调谐微粒凝胶大小展示。这种方法非常适合原型新的反应的组合物和条件或用于不需要大量产品的应用程序。微凝胶合成，颗粒大小和结构测定动态和静态光散射在协议中详细介绍。它表明在加入官能共聚单体可具有在颗粒成核和结构有很大的影响。通过宽视场荧光显微镜单粒子跟踪允许标记的示踪剂微粒凝胶的扩散的非标记的微凝胶的浓缩矩阵调查，系统不易受调查其他方法，如动态光散射。

PNIPAM微粒凝胶颗粒的批次中从而最终颗粒体积的数量，而且，在成核阶段20疏水共聚单体染料甲基丙烯酰硫代若丹明B通过减少在间歇的粒子数密度影响成核过程中的反应初确定。为两个不同的初始NIPAM浓度颗粒浓度的降低可以被看作是在折叠状态与染料浓度的增加，平均最终颗粒的体积增加，在图1所示的体积的增加可以归因于所述的疏水共聚单体染料，它促进微粒凝胶核聚集在早期的反应时间，从而降低了颗粒浓度并增加最终颗粒体积。 从一个成功的DLS measuremen结果TS示于图2中 。关于Q 2和内误差零截距的平均衰减率Γ2的六个最小最终颗粒体积批次线性关系表明，对于这些批次的粒度分布是相对窄和阱对于平均扩散系数-defined估计可以从线性拟合的斜率来获得的。 图3示出了从两个最大体积批次，其中Γ2从中间q系列，线性行为偏离的更复杂的结果。非线性从外形（角散射图案）最小其与这些的Q值相一致起源28中的问题的现象可以为颗粒被观察其尺寸相媲美的入射激光辐射的波长，甚至一适中的粒度分布宽度。扩散系数在这个问答测定</em&gt;在强烈的偏见导致的结果范围，从而造成错误描述的一个显着的风险。在图3的具体情况下，Γ2再次反映了平均行为在高q，其中所有颗粒级的总散射强度有助于更均匀。一个直接的方法以获得用于均值扩散系数的合理估计是从线性拟合排除中间Γ2的值。如果该粒子的形状因子是已知的，更精细的拟合方法可以使用28。 确定在所述折叠状态下的流体动力学体积而不让样品冷却下来下面PNIPAM VPTT确保非凝胶溶胶级分还没有从所述颗粒分离。因此在折叠状态下的体积反映了质量和颗粒的聚合过程中的数量，这是如果fundam重要沉淀聚合ental属性正在研究20。在折叠状态的体积也提供了一个很好的量，比较不同的反应参数，因为它是独立的溶胀性质和非胶凝聚合物在由交联剂在单体混合物中的量来调节颗粒的级分。尺寸更小，在折叠状态下更高对比度的散射也方便DLS表征。 在642纳米和用于基质和示踪粒子404毫微米两个波长测定静态光散射数据示于图4中的角散射图案的目视检查表明，颗粒是明确定义:典型的整个球形颗粒多重分辨振荡第q分别表示窄的多分散，在这种情况下，7％和6％的示踪物和基质微凝胶。光滑behavior在低Q表示该样品被充分稀释，并没有显著颗粒聚集存在。在极端中的q散射强度的增加可以归因于散射由于背面反射从内反应杯壁光束。基质颗粒的形式因素的反转确认典型微粒凝胶结构29与致密核心和从交联剂共聚动力学30（见插图）所得径向衰减密度分布。虚线示出了具有回转相同平均半径作为基质粒子的参考硬球的形状因数。实验的外形符合Q比硬球的外形，这是典型的模糊与颗粒表面的衰减速度更快。与此相反，示踪颗粒具有非常规的微粒凝胶结构。这可从参考硬球的外形，这表明实验外形最初不被也看到衰减比基准速度更快。这个结果表明，掺入的染料分子以微凝胶可影响它们的结构，必须以对结果的解释予以考虑。 合成的颗粒的均匀性高是在围绕玻璃化转变温度的体积分数为他们的扩散研究高息，以精确地确定在此制度13演变行为，并将其与硬质颗粒31。因此，标记的微凝胶的低级分具有可比尺寸的非标记的微粒凝胶混合。用激发波长和过滤器配置在发射路径中使用沿微粒凝胶掺入的染料分子的激发和发射光谱示于图5中。吸光度和甲基丙烯酰硫代若丹明B是接近激发波长和荧光收集范围发射最大值，分别实现了粒子跟踪设置集热效率高。均方位移用于各种非标记的微凝胶基质浓度示踪剂微粒凝胶的时间演变分别示于图6和图7中的线性和对数刻度。在低微凝胶基质浓度的示踪粒子迅速扩散。即使它们移出焦点平面的前只对帧的数量有限的可见，它们的平均方位移的一个合理的良好估计是可能的。均方位移随时间的线性增加指示测量的所有时间滞后的正常扩散行为。然而，对于微粒凝胶的浓度接近胶体玻璃化转变， 即，29-36毫克/毫升，均方位移的时间演化成为非线性（参见图7）。行为类似于胶体微米尺寸的PMMA颗粒作为内容描述的所述一个由Weeks ribed和韦茨31和可与该笼效应。如在图10中示意性示出，在致密基质的标记微凝胶可在笼子内，而自由扩散。出于这个原因，所述均方位移中的第几毫秒线性增加。然而，由于颗粒被截留在其邻国形成短暂的笼子，周围的微凝胶集体重排是必要的​​微凝胶进一步移动。这个笼效应表现在一个相当浅的斜率在图7的第二范围，并且可以通过在图9中检查粒子径迹来也证实，在短暂的延迟时间的颗粒轻摇在它们的笼子，从中他们逃脱只是为了得到再次被困。在很长的时间滞后，线性扩散行为被回收。凯奇的效果可以用反常扩散模型，其中的时空演化（二维检测）的意思是美商分析isplacement由功法在时间上表示: <img alt="24式" src="/files/ftp_upload/54419/54419eq24.jpg" />或在其对数形式<img alt="25式" src="/files/ftp_upload/54419/54419eq25.jpg" />该异常参数<img alt="26式" src="/files/ftp_upload/54419/54419eq26.jpg" /> 32。对于正常扩散，异常参数等于1，次扩散由值以下。 图8显示在对数-对数曲线图。图7的斜率直接确定异常参数的时间演变来表示。对于较低浓度的在我们的研究微凝胶，异常的参数基本上等于1。对于滞后时间<img alt="27式" src="/files/ftp_upload/54419/54419eq27.jpg" />在几秒钟的范围内，该因子偏离1向较低值。此行为是一个工件由于事实，即在宽视场显微镜的轴向（z轴）观察范围被限制到只有几微米。狭窄的Z-范围内长的时间间隔为偏置快速扩散的分析，在低浓度基质扩散迅速示踪剂。当增大微粒凝胶浓度，我们发现，异常参数的最小变得更加明显，过渡到正常扩散（ <img alt="28式" src="/files/ftp_upload/54419/54419eq28.jpg" /> ）后出现。这是接近其玻璃化转变体制时出现密集微凝胶系统笼效应明确指示。 <img alt="图1" src="/files/ftp_upload/54419/54419fig1.jpg" /> 图1: 单粒子量折叠状态与在批初始染料浓度使用了两种不同的初始NIPAM浓度，57.5毫摩尔分米-3（黑色圆圈）和28.8毫摩尔分米-3（灰色矩形）。用交联剂的1摩尔％。初始KPS浓度在所有的蝙蝠一样CHES 1.56毫摩尔DM -3。误差线表示标准偏差。 <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/54419/54419fig1large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <img alt="图2" src="/files/ftp_upload/54419/54419fig2.jpg" /> 图2: 衰减速率与四个最小体积微粒凝胶分批散射矢量幅度的平方的线性依赖性。 <img alt="29式" src="/files/ftp_upload/54419/54419eq29.jpg" />关于Q 2和零截距表示窄的粒度分布，并表明平均扩散系数的定义良好的估计可以从线性拟合的斜率来计算。 NIPAM浓度分别为57.5毫摩尔DM -3（红色正方形和橙色的倒三角）和28.8毫摩尔DM -3（符号的其余部分）。染料浓度分别为0.044毫摩尔ð米-3（红色方块），0.022毫摩尔DM -3（橙色倒三角），0.088毫摩尔DM -3（绿色三角形），0.066毫摩尔DM -3（青色菱形），0.044毫摩尔DM -3（深蓝色三角形），和0.022毫摩尔DM -3（粉红色圆圈）。 <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/54419/54419fig2large.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/54419/54419fig3.jpg" /> 图 3: 衰减率与两个最大体积批次散射矢量幅度的平方与Q 2中的中心Q系列，Γ2的非线性行为由不同大小的级分中的信号的强度的加权的变化所引起在外形最小的附近。在两批NIPAM浓度分别为57.5毫摩尔DM-3，染料浓度分别为0.088毫摩尔DM -3（黑圈）和0.066毫摩尔DM -3（红色三角形）。褪色的符号被排除在线性拟合。 <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/54419/54419fig3large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <img alt="图4" src="/files/ftp_upload/54419/54419fig4.jpg" /> 图 4: 标记的示踪剂和未标记的基质颗粒形式的因素对于外形在两个波长，642纳米（淡蓝色和红色数据点）和404纳米（绿和深蓝的数据点）测得的两个颗粒。实线是全球适配到642 nm和404 nm的数据集。虚线显示具有回转半径相同为基体，示踪粒子硬球参考颗粒的形状因子（橙色和绿色分别为虚线。）插图显示颗粒归从核心到计算，表面密度分布如 FitIt！ <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/54419/54419fig4large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <img alt="图5" src="/files/ftp_upload/54419/54419fig5.jpg" /> 图 5: 荧光标记的微凝胶粒子的激发和发射光谱蓝线表示的激励和红线发射光谱。垂直实线是激发波长。阴影区表示荧光采集的波长范围。 <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/54419/54419fig5large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <img alt="图6" src="/files/ftp_upload/54419/54419fig6.jpg" /> 图6: 均方DISPlacement与滞后时间的示踪的颗粒。未标记的基质微粒凝胶浓度为15.56毫克/毫升（左），22.05毫克/毫升，28.28毫克/毫升，28.67毫克/毫升，30.32毫克/毫升，31.13毫克/ ml和35.35毫克/毫升。点及误差棒分别表示实验值和标准偏差。实线是线性拟合到数据点。插图显示示踪剂微凝胶为35.35毫克/毫升矩阵浓度的宽视场荧光显微镜照片。 <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/54419/54419fig6large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <img alt="图7" src="/files/ftp_upload/54419/54419fig7.jpg" /> 图 7: 均方位移的滞后时间为在对数标度的示踪粒子未标记的基质微粒凝胶浓度为15.56毫克/毫升（左），22.05毫克/毫升，28.28毫克/毫升，28.67毫克/毫升，30.32毫克/毫升， 31.13毫克/毫升和35.3<html> 5毫克/毫升。点及误差棒分别表示实验值和标准偏差。实线是多项式拟合的数据点。 <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/54419/54419fig7large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <img alt="图8" src="/files/ftp_upload/54419/54419fig8.jpg" /> 图8: 异常参数与滞后时间为示踪粒子未标记的基质微粒凝胶浓度为15.56毫克/毫升（左），22.05毫克/毫升，28.28毫克/毫升，28.67毫克/毫升，30.32毫克/毫升，31.13毫克/ ml和35.35毫克/毫升。点表示用有限差分和实线分析计算从多项式拟合衍生品在图7估计衍生物<a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/54419/54419fig8large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> e_content"FO: - together.within页保留="1"&gt; <img alt="图9" src="/files/ftp_upload/54419/54419fig9.jpg" /> 图9:粒子轨迹为色散12示踪剂微凝胶与35.35毫克/毫升的基质浓度曲目从示踪的颗粒独特的斑点结果被困在其未标记的邻国形成短暂的笼子聚类<a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/54419/54419fig9large.jpg" target="_blank">请点击这里查看大图这个数字。</a> <img alt="图10" src="/files/ftp_upload/54419/54419fig10.jpg" /> 图10: 在浓未标记基质微粒凝胶分散体示踪微粒凝胶扩散的示意图红色轨迹表示瞬态笼子内的示踪剂的快速扩散（蓝色虚线）由相邻的颗粒形成的。蓝色轨迹表示长的滞后TI通过瞬态网箱集体重排，使我的扩散。 <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/54419/54419fig10large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <img alt="图11" src="/files/ftp_upload/54419/54419fig11.jpg" /> 图11: 用未标记的基质微粒凝胶浓度长滞后时间扩散系数在低基质浓度示踪剂微粒凝胶的扩散不受基质粒子。随着微凝胶基质浓度长时间的扩散速度减慢数量级，因为扩散需要短暂的笼子，那里的示踪剂被困集体重排。 <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/54419/54419fig11large.jpg" target="_blank">请点击此处查看该图的放大版本。</a>

Watch this Scientific Journal Video about Controlled Synthesis and Fluorescence Tracking of Highly Uniform PolyN-isopropylacrylamide Microgels at JoVE.com

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

非搅拌沉淀聚合提供了一种快速，可重复的成型方法来刺激敏感聚（N- -isopropylacrylamide）粒径分布窄的微粒凝胶的合成。在这个协议中合成，光散射表征和在宽视场显微镜设置这些微粒凝胶的单个粒子荧光跟踪被证明。

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 ...

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Nanyang Technological University

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Chemistry

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

10.1K 次观看.  RWTH Aachen University. 非搅拌沉淀聚合提供了一种快速，可重复的成型方法来刺激敏感聚（N- -isopropylacrylamide）粒径分布窄的微粒凝胶的合成。在这个协议中合成，光散射表征和在宽视场显微镜设置这些微粒凝胶的单个粒子荧光跟踪被证明。 

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

Synthesis and Characterization of Functionalized Metal-organic Frameworks

Metal-organic frameworks have attracted extraordinary amounts of research attention, as they are attractive candidates for numerous industrial and technological applications. Their signature property is their ultrahigh porosity, which however imparts a series of challenges when it comes to both constructing them and working with them. Securing desired MOF chemical and physical functionality by linker/node assembly into a highly porous framework of choice can pose difficulties, as less porous and more thermodynamically stable congeners (e.g., other crystalline polymorphs, catenated analogues) are often preferentially obtained by conventional synthesis methods. Once the desired product is obtained, its characterization often requires specialized techniques that address complications potentially arising from, for example, guest-molecule loss or preferential orientation of microcrystallites. Finally, accessing the large voids inside the MOFs for use in applications that involve gases can be problematic, as frameworks may be subject to collapse during removal of solvent molecules (remnants of solvothermal synthesis). In this paper, we describe synthesis and characterization methods routinely utilized in our lab either to solve or circumvent these issues. The methods include solvent-assisted linker exchange, powder X-ray diffraction in capillaries, and materials activation (cavity evacuation) by supercritical CO2 drying. Finally, we provide a protocol for determining a suitable pressure region for applying the Brunauer-Emmett-Teller analysis to nitrogen isotherms, so as to estimate surface area of MOFs with good accuracy.

Synthesis, activation, and characterization of intentionally designed metal-organic framework materials is challenging, especially when building blocks are incompatible or unwanted polymorphs are thermodynamically favored over desired forms. We describe how applications of solvent-assisted linker exchange, powder X-ray diffraction in capillaries and activation via supercritical CO2 drying, can address some of these challenges.

功能化的合成与表征金属 - 有机骨架

Metal-organic frameworks have attracted extraordinary amounts of research attention, as they are attractive candidates for numerous industrial and ...

科研

化学

Synthesis of Poly(N-isopropylacrylamide) Janus Microhydrogels for Anisotropic Thermo-responsiveness and Organophilic/Hydrophilic Loading Capability

Janus microparticles are compartmentalized particles with differing molecular structures and/or functionality on each of their two sides. Because of this unique property, Janus microparticles have been recognized as a new class of materials, thereby attracting a great deal of attention from various research fields. The versatility of these microparticles has been exemplified through their uses as building blocks for self-assembly, electrically responsive actuators, emulsifiers for painting and cosmetics, and carriers for drug delivery. This study introduces a detailed protocol that explicitly describes a synthetic method for designing novel Janus microhydrogels composed of a single base material, poly(N-isopropylacrylamide) (PNIPAAm). Janus microdroplets are firstly generated via a hydrodynamic focusing microfluidic device (HFMD) based on the separation of a supersaturated aqueous NIPAAm monomer solution and subsequently polymerized through exposure to UV irradiation. The resulting Janus microhydrogels were found to be entirely composed of the same base material, featured an easily identifiable compartmentalized morphology, and exhibited anisotropic thermo-responsiveness and organophilic/hydrophilic loading capability. We believe that the proposed method introduces a novel hydrogel platform with the potential for advanced synthesis of multi-functional Janus microhydrogels.

Synthesis of PolyN-isopropylacrylamide Janus Microhydrogels for Anisotropic Thermo-responsiveness and Organophilic/Hydrophilic Loading Capability

We present a protocol to synthesize Janus microhydrogels composed entirely of the same base material, poly(N-isopropylacrylamide) (PNIPAAm), with a clearly compartmentalized structure base on the phase separation of a supersaturated NIPAAm monomer solution. The synthesized Janus microhydrogels show unique properties such as anisotropic thermo-responsiveness and organophilic/hydrophilic loading capability.

合成聚（<em&gt;ñ</em&gt; -isopropylacrylamide）剑锋Microhydrogels各向异性热响应能力和亲有机/亲水承载能力

Janus microparticles are compartmentalized particles with differing molecular structures and/or functionality on each of their two sides. Because of this ...

Highly Stereoselective Synthesis of 1,6-Ketoesters Mediated by Ionic Liquids: A Three-component Reaction Enabling Rapid Access to a New Class of Low Molecular Weight Gelators

In organic chemistry ionic liquids (ILs) have emerged as safe and recyclable reaction solvents. In the presence of a base ILs can be deprotonated to form catalytically active N-Heterocyclic Carbenes (NHCs). Here we have used ILs as precatalysts in the addition of &#945;,&#946;-unsaturated aldehydes to chalcones to form 1,6-ketoesters, incorporating an anti-diphenyl moiety in a highly stereoselective fashion. The reaction has a broad substrate scope and several functional groups and heteroaromatics can be integrated into the ketoester backbone in generally good yields with maintained stereoselectivity. The reaction protocol is robust and scalable. The starting materials are inexpensive and the products can be obtained after simple filtration, avoiding solvent-demanding chromatography. Furthermore, the IL can be recycled up to 5 times without any loss of reactivity. Moreover, the 1,6-ketoester end product is a potent gelator in several hydrocarbon based solvents. The method enables rapid access to and evaluation of a new class of low molecular weight gelators (LMWGs) from recyclable and inexpensive starting materials.

Ionic liquids (ILs) mediate fast, simple and cheap access to 1,6-ketoesters in high diastereoselectivities and good yields. The reaction protocol is robust and the 1,6-ketoesters can be obtained in gram scale after a simple filtration protocol. Moreover, the 1,6-ketoesters are potent gelators in hydrocarbon solvents.

1,6-酮酯高立体选择性合成离子液体介导:三组分反应启用快速进入低分子量胶凝剂的新型类

In organic chemistry ionic liquids (ILs) have emerged as safe and recyclable reaction solvents. In the presence of a base ILs can be deprotonated to form ...

Synthesis and Reaction Chemistry of Nanosize Monosodium Titanate

This paper describes the synthesis and peroxide-modification of nanosize monosodium titanate (nMST), along with an ion-exchange reaction to load the material with Au(III) ions. The synthesis method was derived from a sol-gel process used to produce micron-sized monosodium titanate (MST), with several key modifications, including altering reagent concentrations, omitting a particle seed step, and introducing a non-ionic surfactant to facilitate control of particle formation and growth. The resultant nMST material exhibits spherical-shaped particle morphology with a monodisperse distribution of particle diameters in the range from 100 to 150&#160;nm. The nMST material was found to have a Brunauer-Emmett-Teller (BET) surface area of 285 m2g-1, which is more than an order of magnitude higher than the micron-sized MST. The isoelectric point of the nMST measured 3.34 pH units, which is a pH unit lower than that measured for the micron-size MST. The nMST material was found to serve as an effective ion exchanger under weakly acidic conditions for the preparation of an Au(III)-exchange nanotitanate. In addition, the formation of the corresponding peroxotitanate was demonstrated by reaction of the nMST with hydrogen peroxide.

The surfactant mediated sol-gel synthesis of nanosized monosodium titanate is described, along with preparation of the corresponding peroxide modified material. An ion-exchange reaction with Au(III) is also presented.

纳米尺寸钛酸二氢钠的合成和化学反应

This paper describes the synthesis and peroxide-modification of nanosize monosodium titanate (nMST), along with an ion-exchange reaction to load the ...

A Simple Method for the Size Controlled Synthesis of Stable Oligomeric Clusters of Gold Nanoparticles under Ambient Conditions

Reducing dilute aqueous HAuCl4 with sodium thiocyanate (NaSCN) under alkaline conditions produces 2 to 3 nm diameter nanoparticles. Stable grape-like oligomeric clusters of these yellow nanoparticles of narrow size distribution are synthesized under ambient conditions via two methods. The delay-time method controls the number of subunits in the oligoclusters by varying the time between the addition of HAuCl4 to alkaline solution and the subsequent addition of reducing agent, NaSCN. The yellow oligoclusters produced range in size from ~3 to ~25 nm. This size range can be further extended by an add-on method utilizing hydroxylated gold chloride (Na+[Au(OH4-x)Clx]-) to auto-catalytically increase the number of subunits in the as-synthesized oligocluster nanoparticles, providing a total range of 3 nm to 70 nm. The crude oligocluster preparations display narrow size distributions and do not require further fractionation for most purposes. The oligoclusters formed can be concentrated &#62;300 fold without aggregation and the crude reaction mixtures remain stable for weeks without further processing. Because these oligomeric clusters can be concentrated before derivatization they allow expensive derivatizing agents to be used economically. In addition, we present two models by which predictions of particle size can be made with great accuracy.

We describe a simple method for producing highly stable oligomeric clusters of gold nanoparticles via the reduction of chloroauric acid (HAuCl4) with sodium thiocyanate (NaSCN). The oligoclusters have a narrow size distribution and can be produced with a wide range of sizes and surface coats.

根据环境条件的金纳米粒子的稳定低聚簇的大小控制合成的一种简便方法

Reducing dilute aqueous HAuCl4 with sodium thiocyanate (NaSCN) under alkaline conditions produces 2 to 3 nm diameter nanoparticles. Stable grape-like ...

Synthesis and Characterization of Supramolecular Colloids

Control over colloidal assembly is of utmost importance for the development of functional colloidal materials with tailored structural and mechanical properties for applications in photonics, drug delivery and coating technology. Here we present a new family of colloidal building blocks, coined supramolecular colloids, whose self-assembly is controlled through surface-functionalization with a benzene-1,3,5-tricarboxamide (BTA) derived supramolecular moiety. Such BTAs interact via directional, strong, yet reversible hydrogen-bonds with other identical BTAs. Herein, a protocol is presented that describes how to couple these BTAs to colloids and how to quantify the number of coupling sites, which determines the multivalency of the supramolecular colloids. Light scattering measurements show that the refractive index of the colloids is almost matched with that of the solvent, which strongly reduces the van der Waals forces between the colloids. Before photo-activation, the colloids remain well dispersed, as the BTAs are equipped with a photo-labile group that blocks the formation of hydrogen-bonds. Controlled deprotection with UV-light activates the short-range hydrogen-bonds between the BTAs, which triggers the colloidal self-assembly. The evolution from the dispersed state to the clustered state is monitored by confocal microscopy. These results are further quantified by image analysis with simple routines using ImageJ and Matlab. This merger of supramolecular chemistry and colloidal science offers a direct route towards light- and thermo-responsive colloidal assembly encoded in the surface-grafted monolayer.

A protocol for the synthesis and characterization of colloids coated with supramolecular moieties is described. These supramolecular colloids undergo self-assembly upon the activation of the hydrogen-bonds between the surface-anchored molecules by UV-light.

超分子胶体的合成与表征

Control over colloidal assembly is of utmost importance for the development of functional colloidal materials with tailored structural and mechanical ...

Hydroquinone Based Synthesis of Gold Nanorods

Gold nanorods are an important kind of nanoparticles characterized by peculiar plasmonic properties. Despite their widespread use in nanotechnology, the synthetic methods for the preparation of gold nanorods are still not fully optimized. In this paper we describe a new, highly efficient, two-step protocol based on the use of hydroquinone as a mild reducing agent. Our approach allows the preparation of nanorods with a good control of size and aspect ratio (AR) simply by varying the amount of hexadecyl trimethylammonium bromide (CTAB) and silver ions (Ag+) present in the "growth solution". By using this method, it is possible to markedly reduce the amount of CTAB, an expensive and cytotoxic reagent, necessary to obtain the elongated shape. Gold nanorods with an aspect ratio of about 3 can be obtained in the presence of just 50 mM of CTAB (versus 100 mM used in the standard protocol based on the use of ascorbic acid), while shorter gold nanorods are obtained using a concentration as low as 10 mM.

This paper describes a protocol for the synthesis of gold nanorods, based on the use of hydroquinone as reducing agent, plus the different mechanisms for controlling their size and aspect ratio.

金纳米棒基于对苯二酚合成

Gold nanorods are an important kind of nanoparticles characterized by peculiar plasmonic properties. Despite their widespread use in nanotechnology, the ...

Scale-up Chemical Synthesis of Thermally-activated Delayed Fluorescence Emitters Based on the Dibenzothiophene-S,S-Dioxide Core

We report a procedure to linearly scale-up the synthesis of 2,8-bis(3,6-di-tert-butyl-9H-carbazol-9-yl)dibenzothiophene-S,S-dioxide (compound 4) and 2,8-bis(10H-phenothiazin-10-yl)dibenzothiophene-S,S-dioxide (compound 5) using Buchwald-Hartwig cross-coupling reaction conditions. In addition, we demonstrate a scaled-up synthesis of all non-commercially available starting materials that are required for the amination cross-coupling reaction. In the present article, we provide the detailed synthetic procedures for all of the described compounds, alongside their spectral characterization. This work shows the possibility to produce organic molecules for optoelectronic applications on a large scale, which facilitates their implementation into real world devices.

Scale-up synthesis of highly efficient thermally activated delayed fluorescence emitters is described in the presented article.

基于吩 s-二氧化硫核的热活化延迟荧光发射器的放大化学合成

We report a procedure to linearly scale-up the synthesis of 2,8-bis(3,6-di-tert-butyl-9H-carbazol-9-yl)dibenzothiophene-S,S-dioxide (compound 4) and ...

Synthesis and Mass Spectrometry Analysis of Oligo-peptoids

Peptoids are sequence-controlled peptide-mimicking oligomers consisting of N-alkylated glycine units. Among many potential applications, peptoids have been thought of as a type of molecular information storage. Mass spectrometry analysis has been considered the method of choice for sequencing peptoids. Peptoids can be synthesized via solid phase chemistry using a repeating two-step reaction cycle. Here we present a method to manually synthesize oligo-peptoids and to analyze the sequence of the peptoids using tandem mass spectrometry (MS/MS) techniques. The sample peptoid is a nonamer consisting of alternating N-(2-methyloxyethyl)glycine (Nme) and N-(2-phenylethyl)glycine (Npe), as well as an N-(2-aminoethyl)glycine (Nae) at the N-terminus. The sequence formula of the peptoid is Ac-Nae-(Npe-Nme)4-NH2, where Ac is the acetyl group. The synthesis takes place in a commercially available solid-phase reaction vessel. The rink amide resin is used as the solid support to yield the peptoid with an amide group at the C-terminus. The resulting peptoid product is subjected to sequence analysis using a triple-quadrupole mass spectrometer coupled to an electrospray ionization source. The MS/MS measurement produces a spectrum of fragment ions resulting from the dissociation of charged peptoid. The fragment ions are sorted out based on the values of their mass-to-charge ratio (m/z). The m/z values of the fragment ions are compared against the nominal masses of theoretically predicted fragment ions, according to the scheme of peptoid fragmentation. The analysis generates a fragmentation pattern of the charged peptoid. The fragmentation pattern is correlated to the monomer sequence of the neutral peptoid. In this regard, MS analysis reads out the sequence information of the peptoids.

A protocol is described for the manual synthesis of oligo-peptoids followed by sequence analysis by mass spectrometry.

寡 peptoids 的合成及质谱分析

Peptoids are sequence-controlled peptide-mimicking oligomers consisting of N-alkylated glycine units. Among many potential applications, peptoids have ...

Synthesis of Substrate-Bound Au Nanowires Via an Active Surface Growth Mechanism

Advancing synthetic capabilities is important for the development of nanoscience and nanotechnology. The synthesis of nanowires has always been a challenge, as it requires asymmetric growth of symmetric crystals. Here, we report a distinctive synthesis of substrate-bound Au nanowires. This template-free synthesis employs thiolated ligands and substrate adsorption to achieve the continuous asymmetric deposition of Au in solution at ambient conditions. The thiolated ligand prevented the Au deposition on the exposed surface of the seeds, so the Au deposition only occurs at the interface between the Au seeds and the substrate. The side of the newly deposited Au nanowires is immediately covered with the thiolated ligand, while the bottom facing the substrate remains ligand-free and active for the next round of Au deposition. We further demonstrate that this Au nanowire growth can be induced on various substrates, and different thiolated ligands can be used to regulate the surface chemistry of the nanowires. The diameter of the nanowires can also be controlled with mixed ligands, in which another &#34;bad&#34; ligand could turn on the lateral growth. With the understanding of the mechanism, Au nanowire-based nanostructures can be designed and synthesized.

We report a solution-based method to synthesize substrate-bound Au nanowires. By tuning the molecular ligands used during the synthesis, the Au nanowires can be grown from various substrates with different surface properties. Au nanowire-based nanostructures can also be synthesized by adjusting the reaction parameters.