Understanding hydrophobic interactions in cellulose nanofibres

这笔旅行补助金将使布里斯托尔大学的Stephen Eichhorn教授能够与日本九州大学的近藤哲夫教授在纤维素纳米纤维的疏水相互作用领域开展合作。纤维素是地球上利用率最高的材料。目前的年产量达到惊人的10^12吨。考虑到它的密度，这大约是钢体积的20倍。它主要由植物细胞壁产生，但也可以由一些革兰氏阴性细菌和一种已知的动物(被毛类)产生。纤维素的结构是这样的，装饰组成聚合结构链的糖单元的化学基团参与了类似于冰中的氢键。这就形成了一种二分法，尽管构成纤维素的碱性糖可溶于水，但聚合物纤维素却不溶于水。这通常归因于广泛的氢键存在，但考虑到这种材料不会在大多数溶剂中溶解，这现在被认为不是唯一的因素。最近，纤维素结构中葡萄糖环表面之间的疏水相互作用(两个水的憎恨表面聚集在一起)的概念被认为是其溶剂化的限制因素。对于相对简单的分子，疏水效应本身是众所周知的，但对于纤维素和复杂的大分子，我们的理解还在很大程度上处于发展之中。更好地了解纤维素中的这种效应可能会导致对这种材料的更大开发，特别是通过利用新型纤维素纳米纤维(横向尺寸为100 nm的纤维)某些表面固有的疏水性来将其用于复合材料。这种形式的纤维素纳米纤维是由九州大学的研究小组利用高压水射流--称为水反碰撞--生产出来的。这笔赠款的目的是为了形成一个合作，以更好地了解这种材料的性质。艾希霍恩教授目前有一个由EPSRC资助的大型研究计划，该计划研究使用纤维素纳米纤维形成水凝胶(EP/N03340X/2)；一个潜在的开发领域是它们在复合材料中的应用。近藤教授刚刚从NEDO(新能源和工业技术开发组织)获得了研究热塑性聚合物与纤维素相互作用的可行性研究计划的资助。来自这些赠款的工作，加上这次旅行，将使该小组能够在这一领域建立一些新的研究路线。

This travel grant will enable Prof. Stephen Eichhorn (University of Bristol) to undertake collaborative work together with Prof. Tetsuo Kondo (Kyushu University, Japan) in the area of hydrophobic interactions in cellulose nanofibres. Cellulose is the most utilised material on the planet. Current annual production stands at a staggering 10^12 tonnes. Given its density this is about 20 times the volume of steel. It is primarily produced by plant cell walls but can also by some gram-negative bacteria and one known animal (tunicates). The structure of cellulose is such that chemical groups which decorate the sugar units making up the chains of the polymeric structure, are involved in hydrogen bonding - like in ice. This presents a dichotomy, in that although the basic sugars that make up cellulose are soluble in water, the polymer cellulose is not. This is usually attributed to the extensive hydrogen bonding present but given that the material will not dissolve in most solvents, this is now thought to not be the only contributing factor. Recently, the concept of a hydrophobic interaction (where two water 'hating' surfaces come together) within the cellulose structure, between the faces of the glucose rings, has been postulated - the so-called 'Lindman effect - as a limiting factor in its solvation. The hydrophobic effect itself is well-understood for relatively simple molecules, but for cellulose and complex macromolecules our understanding is still very much in development. Better understanding of this effect in cellulose could lead to greater exploitation of the material, particularly its use in composites by exploiting the inherent hydrophobicity of certain surfaces of a new form of cellulose nanofibre (a fibre with lateral dimensions <100nm). This form of cellulose nanofibre is produced by the group at Kyushu University using high pressure water jets - called Aqueous Counter Collision. The purpose of this grant is to form a collaboration to better understand the properties of this material. Professor Eichhorn currently has a large EPSRC funded program of research investigating the formation of hydrogels (EP/N03340X/2) using cellulose nanofibers; one potential area of exploitation is their use in composite materials. Professor Kondo has just received funding from NEDO (New Energy and Industrial Technology Development Organization)- Feasibility Study Program to study the interaction of thermoplastic polymers with cellulose. The work from these grants, combined with this travel, will enable the group to establish some new research lines in this area.