Cellulosic polymer colloids, polymers and polyelectrolytes

对新兴生物经济的一个重要贡献是在无害环境的过程中将生物质转化为有用的产品。大约五年前，我们有了一个有趣的发现。我们发现了一种新型的纳米纤维素（现在称为毛纳米纤维素，HNC），与传统的纤维素纳米晶体（CNC）和纤维素纳米原纤维（CNF）非常不同。这种新的颗粒由棒状胶体核组成，并含有许多聚合物或聚合物链（“毛发”）。HNC颗粒属于聚合物胶体类。它们可以通过水性方法由脱木质素的木纤维（纤维素纤维）以约50%的产率生产。另外50%由水溶性纤维素衍生物组成。本文将介绍HNC的性质和应用以及水溶性纤维素及其衍生物的性质。我们建议将研究分为7个专题。在主题1“HNC的表征”中，我们将尝试用三种不同的技术对毛发进行成像：（i）用金纳米颗粒（AuNP）标记毛发，然后进行TEM;（ii）使用化学修饰的尖端通过AFM对毛发进行成像;（iii）通过随机光学重建显微镜（STORM）。主题2介绍了由CNC制备的HNC，以及左右手CNC的液晶性质。主题3讨论修剪HNC的聚合。我们已经表明，可以用二胺交联羧化平头HNC（通过生物缀合或点击化学），这导致端对端聚集，因为HNC的几乎所有电荷都位于两端的短毛中。还应该可以通过混合带正电荷和带负电荷的平头HNC来制备细长的纳米原纤维，从而产生其中两种类型的HNC交替的长原纤维。 主题4和主题4涉及HNC和聚合物/HNC复合物膜的防垢性能，通过计时电流法测量。最后，主题6和7分别讨论了纤维素水溶性聚合物和聚电解质的性质。具体而言，我们建议研究纤维素衍生物与二醛基的C2-C3碳纤维素，氧化度（DO）约为1。我们将这些聚合物称为二醛改性纤维素（DAMC），以将它们与DO = 2的二醛纤维素（DAC）区分开。我们建议研究DAMC和DAC的性质，如分子量，分子量和醛基密度的多分散性，持续长度，Flory-Huggins参数（或聚合物-溶剂相互作用参数等），以及它的长期稳定性。所使用的一些技术将是GPC（凝胶渗透色谱法、静态光散射和渗透压测量）。我们将把光开关分子连接到DAMC上，并用STORM对聚合物链进行成像。

An important contribution to the emerging bioeconomy is the conversion of biomass to useful products in environmentally friendly processes. About 5 years ago, we made a fascinating discovery. We discovered a novel type of nanocellulose (now called hairy nanocellulose, HNC), very different from the conventional cellulose nanocrystals (CNC) and cellulose nanofibrils (CNF). The novel particle consists of a rod-shaped colloidal core and contains many polymeric or polyelectrolyte chains (the “hairs”). HNC particles belong to the class of polymer colloids. They can be produced by an aqueous process from delignified wood fibers (cellulose fibers) with a yield of about 50%. The other 50% consists of water-soluble cellulose derivatives. The research proposed here will address properties and applications of HNC and properties of the water soluble cellulosics and derivatives thereof. We propose to organize the research in 7 topics. In topic 1, “Characterization of HNC”, we will attempt imaging the hairs with three different techniques: (i) labeling the hairs with gold nanoparticles (AuNP), followed by TEM; (ii) imaging the hairs by AFM using chemically modified tips; (iii) by Stochastic Optical Reconstruction Microscopy (STORM). Topic 2 deals with HNC produced from CNC, and the liquid crystalline properties of right and left handed CNC. Topic 3 addresses the aggregation of trimmed HNC. We have shown that one can crosslink carboxylated crew cut HNC with a diamine (via bioconjugation or click chemistry), which results in end-to-end aggregation, since almost all the charges of HNC are located in the short hairs at both ends. It should also be possible to make long slender nanofibrils by mixing positively and negatively charged crew cut HNC, resulting in long fibrils in which the two types of HNC alternate. Topics 4 and 4 deal with antiscaling properties of HNC and antifouling membranes of polymer/HNC composites, to be measured by chronoamperometry. Finally topics 6 and 7 deal with the properties of cellulosic water-soluble polymers and polyelectrolyes respectively. Specifically, we propose to study cellulose derivatives with dialdehyde groups on the C2-C3 carbons of cellulose, with a degree of oxidation (DO) of about 1. We refer to these polymers as dialdehyde modified cellulose (DAMC), to distinguish them from dialdehyde cellulose (DAC), for which DO = 2. We propose to study the properties of DAMC and DAC, such as molecular weight, polydispersity in molecular weight and density of aldehyde groups, persistence length, Flory-Huggins - parameter (or polymer-solvent interaction parameter, etc.), as well as its long-time stability. Some of the techniques used will be GPC (gel permeation chromatography, static light scattering and osmotic pressure measurements. We will attach photoswitchable molecules to DAMC and image the polymeric chains with STORM.