<MultiModal>![This image describes two organic structural formulas. The left side is a polymer with three repeating monomers, each with the structure [a]OCC[b], where a and b represent the monomer connection sites. The structure connecting the three a sites is [*]CC(CC)(C[*])C[*], where * represents the site connected to a. The structure connecting the three b sites is [B]OC1=CC=C(C=O)C=C1, where B represents the connection site. The structure on the right is O=C(NN)CCCCC(NN)=O.](/media/uploads/3d63b13a-21a4-45de-b7a1-0dcdb4779d2a.png)</MultiModal>

Some polymer compounds have self-healing properties. The two compounds shown in the figure above can be fully polymerized in aqueous solution to produce a self-healing hydrogel; the degree of repair varies with the pH of the system.

To test the self-healing ability of the hydrogel, a piece of hydrogel was cut open and left to stand for 48 h, and the recovery of the two cut surfaces was observed.

Which of the following statements is correct:
<MultiModal>![本图片描述了两个有机结构式。左边为高分子，具有三个重复单体，其结构均为[a]OCC[b]，其中a,b表示单体连接位点。连接三个a位点的结构为[*]CC(CC)(C[*])C[*]，*表示与a相连的位点。连接三个b位点的结构为[B]OC1=CC=C(C=O)C=C1，B表示连接位点。右边结构为O=C(NN)CCCCC(NN)=O。](/media/uploads/3d63b13a-21a4-45de-b7a1-0dcdb4779d2a.png)</MultiModal>

有些高分子化合物具有自修复功能，上图所示的两种化合物在水溶液中充分聚合，可制成一种自修复水凝胶；随体系pH不同，修复程度也不相同。

为测试水凝胶的自修复能力，取一块水凝胶切开后静置48 h，观察两侧切面的恢复情况。

下列说法正确的是：
All other options are incorrect
Replacing the monomer structure in the polymer with polyethylene monomers results in hydrogels with similar properties.
pH=8-10, the cut surfaces on both sides will adhere.
pH=1~4, the two cut surfaces will adhere.
pH=4~6, the two cut surfaces will not adhere.
pH=7-8, a catalytic amount of aniline exists in the system, and the cut surfaces on both sides will adhere.
At pH=7, the two cut surfaces will adhere.
其他选项均不正确
高分子中的单体结构用聚乙烯单体替换后，得到的水凝胶具有类似的性质
pH=8-10时，两侧切面会发生粘合
pH=1~4时，两侧切面会发生粘合
pH=4~6时，两侧切面不会发生粘合
pH=7-8时，体系中存在催化量的苯胺，两侧切面会发生粘合
pH=7时，两侧切面会发生粘合
The polymer's monomer is polyethylene glycol, which can form hydrogen bonds with water, thereby enhancing hydrophilicity. Therefore, if it is replaced with a polyethylene segment that does not contain oxygen atoms, it will not be hydrophilic, so option B is incorrect.

<Checkpoint>[The polymer's monomer is polyethylene glycol, which can form hydrogen bonds with water, thereby enhancing hydrophilicity](1)</Checkpoint>

Weakly acidic conditions can catalyze the hydrolysis of imine bonds and the condensation reaction of amino and aldehyde groups, thereby forming a dynamic equilibrium. Acid catalysis realizes the reversible exchange of chemical bonds, promotes the reformation of the hydrogen bond network, and achieves self-healing of the cut surface. Therefore, when pH=4~6, the cut surface can automatically heal, and options C and E are incorrect.

<Checkpoint>[Weakly acidic conditions can catalyze the hydrolysis of imine bonds and the condensation reaction of amino and aldehyde groups](1)</Checkpoint>

<Checkpoint>[Acid catalysis realizes the reversible exchange of chemical bonds, promotes the reformation of the hydrogen bond network, and achieves self-healing of the cut surface](1)</Checkpoint>

Under strongly acidic conditions, the hydrolysis of the imine bond is very thorough, and the polymer will be completely hydrolyzed, so gel healing cannot be observed, and option D is incorrect.

<Checkpoint>[Under strongly acidic conditions, the hydrolysis of the imine bond is very thorough, and the polymer will be completely hydrolyzed](1)</Checkpoint>

When pH=7, the concentration of hydrogen ions is too low, and dynamic equilibrium is difficult to achieve, so healing cannot be observed, and option G is incorrect.

<Checkpoint>[When pH=7, the concentration of hydrogen ions is too low, and dynamic equilibrium is difficult to achieve](1)</Checkpoint>

However, in the presence of aniline, aniline can act as a nucleophilic catalyst, performing nucleophilic attack on the imine and leaving, promoting the imine hydrolysis reaction, so healing can be observed, and option F is correct.

<Checkpoint>[Aniline can act as a nucleophilic catalyst, performing nucleophilic attack on the imine and leaving, promoting the imine hydrolysis reaction](1)</Checkpoint>
高分子的单体为聚乙二醇，其能与水形成氢键，从而增强亲水性，因此若换为不含氧原子的聚乙烯链段时不具有亲水性，选项B错误。

<Checkpoint>[高分子的单体为聚乙二醇，其能与水形成氢键，从而增强亲水性](1)</Checkpoint>

弱酸性条件可催化亚胺键的水解反应，以及氨基与醛基的缩合反应，从而形成动态平衡，通过酸催化实现化学键的可逆交换，促进氢键网络的重新形成，实现切面自愈合。因此pH=4~6时，切面可自动愈合，选项C,E错误。

<Checkpoint>[弱酸性条件可催化亚胺键的水解反应，以及氨基与醛基的缩合反应](1)</Checkpoint>

<Checkpoint>[酸催化实现化学键的可逆交换，促进氢键网络的重新形成，实现切面自愈合](1)</Checkpoint>

强酸性条件下，亚胺键的水解非常彻底，聚合物会彻底水解，因此观察不到凝胶愈合，选项D错误。

<Checkpoint>[强酸性条件下，亚胺键的水解非常彻底，聚合物会彻底水解](1)</Checkpoint>

pH=7时，氢离子浓度过低，动态平衡难以实现，因此观察不到愈合，选项G错误。

<Checkpoint>[pH=7时，氢离子浓度过低，动态平衡难以实现](1)</Checkpoint>

但苯胺存在时，苯胺可作为亲核性催化剂，对亚胺进行亲核进攻且可离去，促进了亚胺水解反应，因此可观察到愈合，选项F正确。

<Checkpoint>[苯胺可作为亲核性催化剂，对亚胺进行亲核进攻且可离去，促进了亚胺水解反应](1)</Checkpoint>