In $DMF$ solvent, a small amount of polymer $\mathbf{A}$ (as shown in Fig. 1) and a large amount of monomer $\mathbf{1}$ (as shown in Fig. 2) were added and reacted at $30^{\circ} \mathrm{C}$ for 3 days to precipitate the block copolymer $\mathbf{B}$. Studies have shown that when $\mathbf{B}$ is dissolved in a $DMF-H_2O(40:60)$ mixed solution, it will self-assemble to form spherical micelles. When the system was irradiated with ultraviolet light with a wavelength of 254 nm, it was found that the average diameter of the spherical micelles decreased significantly; infrared spectroscopy showed that the absorption peak at $965  \mathrm{~cm}^{-1}$ gradually weakened to disappear during the irradiation process.

<MultiModal>![Fig. 1, the structure of $\mathbf{A}$ is shown in the figure, and its repeating unit is represented by SMILES as [Y]CCO[Z], where [Y] and [Z] refer to being connected to the polymer backbone. The polymer terminal structure in the [Y] direction is CO[Y], where [Y] refers to being connected to the polymer backbone. The polymer terminal structure in the [Z] direction is NCC[Z], where [Z] refers to being connected to the polymer backbone.](/media/uploads/3af31f9b-a2f0-4134-9552-bf044863c85b.png)</MultiModal>

<MultiModal>![Fig. 2, the molecule in the figure is represented by SMILES as: O=C(CCC1C(OC(N1)=O)=O)OC/C=C/C2=CC=CC=C2](/media/uploads/daf83a56-774e-4b9a-b30d-be3ab89e3687.png)</MultiModal>

Infer the structure of the block copolymer $\mathbf{B}$, the reason why it spontaneously forms spherical micelles in the $DMF-H_2O(40:60)$ mixed solution, and the reason why the diameter of the micelles decreases under ultraviolet light irradiation. There are the following statements:

1.  The number of carbon-oxygen double bonds in the reactants participating in the reaction is almost equal to the number of carbon-oxygen double bonds in the obtained product.
2.  If the side chain in monomer $\mathbf{1}$ is replaced with polyethylene glycol, the product may not be able to self-assemble to form spherical micelles.
3.  Ultraviolet light irradiation causes some groups of polymer molecules to dissociate, resulting in a decrease in the average diameter of the micelles.
4.  The change in the infrared spectrum comes from the disappearance of the carbon-oxygen double bond.

Which of the following options contains all the correct statements and the largest number of correct statements:
在 $DMF$溶剂中, 加入少量的聚合物 $\mathbf{A}$ （如图1）和大量的单体$\mathbf{1}$（如图2）, 于 $30^{\circ} \mathrm{C}$ 下反应3天，沉淀出嵌段共聚物$\mathbf{B}$。研究表明,$\mathbf{B}$溶于$DMF-H_2O(40:60)$混合溶液时,会通过自组装形成球状胶束。使用波长为254nm的紫外光对体系进行照射,发现球状胶束的平均直径发生了明显的缩小; 红外光谱表明, 照射过程中位于$965  \mathrm{~cm}^{-1}$  处的吸收峰逐渐减弱至消失。

<MultiModal>![Fig. 1，图中为$\mathbf{A}$ 的结构，其重复单元以SMILES表示为[Y]CCO[Z]，其中[Y]和[Z]分别指连接到聚合物主链上。[Y]方向的聚合物末端结构为CO[Y]，其中[Y]指连接到聚合物主链上。[Z]方向的聚合物末端结构为NCC[Z]，其中[Z]指连接到聚合物主链上。](/media/uploads/3af31f9b-a2f0-4134-9552-bf044863c85b.png)</MultiModal>

<MultiModal>![Fig. 2，图中分子以SMILES表示为：O=C(CCC1C(OC(N1)=O)=O)OC/C=C/C2=CC=CC=C2](/media/uploads/daf83a56-774e-4b9a-b30d-be3ab89e3687.png)</MultiModal>

推断嵌段共聚物$\mathbf{B}$的结构，其在$DMF-H_2O(40:60)$混合溶液中自发形成球状胶束的原因，以及胶束在紫外光照射下直径缩小的原因。有以下几种说法：

1. 参与反应的反应物中碳氧双键数量与得到产物中碳氧双键数量几乎相等
2. 若把单体$\mathbf{1}$中的侧链替换为聚乙二醇，则产物可能无法自组装形成球状胶束
3. 紫外光照射导致聚合物分子的一部分基团发生解离，造成胶束平均直径缩小
4. 红外光谱的变化来自于碳氧双键的消失

下列选项中说法全部正确且正确说法数量最多的是：
All other options are incorrect
1
2
3
4
1,2
1,3
1,4
2,3
2,4
3,4
1,2,3
1,2,4
2,3,4
1,3,4
1,2,3,4
其他选项均不正确
1
2
3
4
1,2
1,3
1,4
2,3
2,4
3,4
1,2,3
1,2,4
2,3,4
1,3,4
1,2,3,4
Polymer $\mathbf{A}$ has active amino groups, which can attack the anhydride carbonyl group in monomer $\mathbf{1}$, undergo ring-opening and decarboxylation to generate new active amino groups. The new active amino groups react with the next molecule of monomer $\mathbf{1}$, causing the ring-opening polymerization reaction chain to grow. The final product is a block polymer $\mathbf{B}$, with one part being polymer $\mathbf{A}$ and the other part having a backbone connected by amide bonds and side chains of monomer $\mathbf{1}$. During the polymerization process, carboxyl groups are lost and the number of carbon-oxygen double bonds decreases, so statement 1 is incorrect.

<Checkpoint>[Polymer $\mathbf{A}$ undergoes ring-opening polymerization with monomer $\mathbf{1}$](1)</Checkpoint>

Because $\mathbf{B}$ has a hydrophilic (or can form hydrogen bonds with water) polyethylene glycol block and a polyamide block with hydrophobic side chains; the polyamide block self-assembles through hydrophobic effects to form the core, and the polyethylene glycol block is exposed to the outside, forming spherical micelles. If the side chains in monomer $\mathbf{1}$ are replaced with polyethylene glycol, the product's two polymer segments will both be hydrophilic, and it may not be able to self-assemble into spherical micelles, so statement 2 is correct.

According to the IR spectrum, $965  \mathrm{~cm}^{-1}$: the characteristic absorption peak of trans-disubstituted carbon-carbon disappears, indicating that ultraviolet irradiation causes the carbon-carbon double bonds on the side chains to undergo [2+2] cycloaddition dimerization, and the distance between the side chains decreases, leading to the spherical micelles becoming smaller. Statements 3 and 4 are incorrect.

<Checkpoint>[Ultraviolet irradiation causes the carbon-carbon double bonds on the side chains to undergo [2+2] cycloaddition dimerization, and the distance between the side chains decreases](1)</Checkpoint>
聚合物 $\mathbf{A}$ 具有活性氨基，可以进攻单体$\mathbf{1}$ 中的酸酐羰基，开环并脱羧产生新的活性氨基。新的活性氨基与下一分子单体$\mathbf{1}$反应使得开环聚合反应链增长。最终得到一部分为聚合物$\mathbf{A}$，另一部分为骨架以酰胺键连接、侧链为单体$\mathbf{1}$中侧链的嵌段聚合物$\mathbf{B}$。聚合过程中有羧基失去，碳氧双键数量减少，说法1错误。


<Checkpoint>[聚合物$\mathbf{A}$与单体$\mathbf{1}$发生开环聚合反应](1)</Checkpoint>

因为 $\mathbf{B}$ 具有亲水(或能与水形成氢键)的聚乙二醇嵌段以及带有疏水侧链的聚酰胺嵌段;聚酰胺嵌段通过疏水效应自组装形成内核,聚乙二醇嵌段暴露在外部,形成球
状胶束。把单体$\mathbf{1}$中的侧链替换为聚乙二醇，则产物前段聚合物两段均亲水，可能无法自组装形成球状胶束，说法2正确。


根据IR谱，$965  \mathrm{~cm}^{-1}$  ：反式二取代碳碳特征吸收峰消失，说明紫外照射导致侧链上的碳碳双键发生[2+2]环加成二聚，侧链间距离缩小，导致球状胶束变小。说法3, 4错误。

<Checkpoint>[紫外照射导致侧链上的碳碳双键发生[2+2]环加成二聚，侧链间距离缩小](1)</Checkpoint>