创新背景

聚合物是由单体的重复小分子组成的长链分子或大分子，通过连接重复的化学单元来构建，单体通过链连接。一个聚合物的每个分子可由数百个、数千个甚至数百万个重复单位组成，随着链的发展，聚合物的结构决定了其独特的物理和化学性质。
聚合物存在于我们在日常生活中使用的许多东西中，它可以是天然的，也可以是合成的。天然聚合物包括DNA、蛋白质、丝绸、明胶和胶原蛋白等材料。合成聚合物由许多不同种类的材料组成，包括塑料、用于构建从玩具到工业电缆再到刹车片的所有材料。
科学家不断研究聚合物，探索它们形成和构建的机制以及如何发展这些独特的性质，了解这些信息有助于开发聚合物的新用途，并创造可用于各种行业的新材料。

创新过程

韩国科学技术学院的Minjoong Shin教授和Myungeun Seo教授研究两亲性随机共聚物的水溶液，在其中发现了新的聚合物中间相结构——双层折叠层状中间相。相关研究成果《由随机聚合物序列诱导的双层折叠层状中间相》发表在2022年5月4日出版的《自然通讯》上。

研究是通过随机共聚物序列发现双层折叠层状中间相的，新的中间相展示了分子自组织的新方法。研究人员表示，因为在热力学上折叠纯双层膜很难，所以新的层状中间相的发现非常重要。
双层折叠层状中间相的来源在研究人员的假设中应该是共聚物中单体的序列。由两种或两种以上单体共同参加的聚合反应形成的含有两种或两种以上单体单元的聚合物称为共聚物。

许多共聚物是随机排列组合形成的，它们的结构依赖于单体之间的相互作用。不同的单体在构成共聚物的链中进行自我排列，不同的自我排列方式可能对共聚物的作用产生影响。疏水性单体之间的相互作用与共聚物链相关联，以隐藏疏水域免受水的影响。研究发现，随着结构逐渐变得复杂，单体在链中的自我排列会呈现出一个可见的发展顺序，使单体可以与正确的对相匹配。周期性顺序会基于单体的集体行为从随机共聚物序列中自发产生。研究人员认为，这表明为长序列找到一个完全互补的对相几乎是不可能的。

在此基础上，研究发现了新的独特中间相结构。共聚物自发折叠并形成被水分离的多层结构，多层结构是板状褶皱状态，折叠的层彼此堆叠，产生的中间相是双折射的。光通过共聚物折射时它会类似液晶，具有粘弹性，这意味着多层结构同时具有粘性和弹性。
研究进一步探索新的中间相，试图明确控制折叠频率并调整折叠高度。研究更多的序列，再次了解中间相及其形成方式，有可能帮助发现新的中间相。

创新价值

有助于了解不同的多序列如何与另一个序列相关联，为未来创建秩序并应用知识来开发新材料提供可能。

Discovery of new polymer intermediate phase structures by random copolymer sequences

Professor Minjoong Shin and Professor Myungeun Seo of the Korea Institute of Science and Technology studied aqueous solutions of amphiphilic random copolymers, in which a new polymer intermediate phase structure was discovered, a bilayer folded layered intermediate phase. The research result "Bilayer Folding Layered Intermediate Phase Induced by Random Polymer Sequence" was published in nature communications published on May 4, 2022.

Studies have found bilayer folded layered intermediate phases through random copolymer sequences, and the new intermediate phases demonstrate new methods of molecular self-organization. The researchers say the discovery of a new layered intermediate phase is important because it is difficult to fold pure bilayer membranes thermodynamically.

The source of the bilayer folded layered intermediate phase should be the sequence of monomers in the copolymer in the researchers' hypothesis. Polymers containing two or more monomer units formed by a polymerization reaction in which two or more monomers participate together are called copolymers.

Many copolymers are formed by random arrangements, and their structure depends on the interactions between the monomers. Different monomers self-align in the chains that make up the copolymer, and different self-arranged patterns may have an impact on the action of the copolymer. Interactions between hydrophobic monomers are associated with copolymer chains to hide the hyoptic waters from water. The study found that as the structure gradually became more complex, the self-arrangement of the monomers in the chain would present a visible order of development, so that the monomers could match the correct pairs. Periodic sequences arise spontaneously from random copolymer sequences based on the collective behavior of the individuals. The researchers believe this suggests that finding a perfectly complementary pair for long sequences is almost impossible.

On this basis, the study found a new unique intermediate phase structure. The copolymers spontaneously fold and form a multilayer structure separated by water, the multilayer structure is a plate-like fold state, the folded layers are stacked on top of each other, and the resulting intermediate phase is birefringent. When light is refracted through a copolymer it resembles a liquid crystal and has viscoelasticity, which means that the multilayer structure is both viscous and elastic.

The study further explores the new intermediate phase, trying to clearly control the folding frequency and adjust the folding height. Studying more sequences and understanding the intermediate phases again and how they form may help discover new intermediate phases.