Understanding hydrophobic interactions in cellulose nanofibres

这笔旅费赠款将使Stephen Eichhorn教授（布里斯托大学）能够与Tetsuo Kondo教授（日本九州大学）在纤维素纳米纤维的疏水相互作用领域开展合作。纤维素是地球上使用最多的材料。目前的年产量为惊人的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（被囊动物）产生。纤维素的结构是这样的，修饰构成聚合结构链的糖单元的化学基团参与氢键结合--就像冰中的氢键结合一样。这就提出了一个二分法，即虽然构成纤维素的基本糖可溶于水，但聚合物纤维素不溶于水。这通常归因于存在的大量氢键，但考虑到材料不会溶解在大多数溶剂中，现在认为这不是唯一的影响因素。最近，纤维素结构内葡萄糖环表面之间的疏水相互作用（其中两个“憎水”表面聚集在一起）的概念已经被假定-所谓的“林德曼效应”-作为其溶剂化的限制因素。对于相对简单的分子，疏水效应本身已经得到了很好的理解，但对于纤维素和复杂的大分子，我们的理解仍在不断发展。更好地理解纤维素中的这种效应可能会导致对该材料的更大开发，特别是通过利用新型纤维素纳米纤维（横向尺寸<100 nm的纤维）某些表面的固有疏水性，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使用高压水射流生产的-称为水逆碰撞。该补助金的目的是形成一个合作，以更好地了解这种材料的属性。Eichhorn教授目前有一个大型的EPSRC资助的研究计划，研究使用纤维素纳米纤维形成水凝胶（EP/N 03340 X/2）;一个潜在的开发领域是它们在复合材料中的应用。近藤教授刚刚获得NEDO（新能源和工业技术开发组织）的资助-可行性研究计划，研究热塑性聚合物与纤维素的相互作用。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.