为什么塑料也能导电？
Why can plastic conduct electricity?
白川英树（2000诺奖）发现掺杂后的聚乙炔能导电，打破了塑料必绝缘的成见，催生了柔性屏、可充电池等新材料。
Hideki Shirakawa (2000 Nobel) found doped polyacetylene conducts electricity, overturning plastics-are-insulators and enabling flexible displays and batteries.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
邢其毅 等,《基础有机化学》第4版,北京大学出版社,2016
Xing Qiyi et al., Basic Organic Chemistry, 4th ed., Peking University Press, 2016
独立核验依据 · Independent verification: 核验依据 2 ISBN 9787301272121（豆瓣书目条目: 基础有机化学）
#导电塑料 #聚乙炔 #白川英树
橡胶拉伸时为什么会发热，这和化学键有什么关系？
Why does stretched rubber warm up, and what does entropy have to do with it?
橡胶由交联的长链高分子组成，未拉伸时分子链卷曲、可用构象数（熵）大；拉伸时被强迫拉直，构象数减少、熵下降。根据热力学，橡胶的弹性主要源于熵变而非键能：快速拉伸时熵减使内能小幅上升而发热，松手回弹则熵增、吸热而变凉。所以橡胶的弹性是“熵弹性”，与金属弹簧的“能弹性”机制相反。
Rubber is a network of cross-linked long polymer chains. Unstretched, the chains are coiled and have many possible conformations (high entropy); stretching forces them straight, reducing the number of conformations and lowering entropy. Thermodynamically, rubber's elasticity comes mainly from this entropy change rather than bond energy: quick stretching lowers entropy, raises internal energy a bit, and warms the rubber, while releasing it lets entropy rise and the rubber cools. So rubber shows entropy elasticity, the opposite of a metal spring's energy elasticity.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
邢其毅 等,《基础有机化学》第4版,北京大学出版社,2016
Xing Qiyi et al., Basic Organic Chemistry, 4th ed., Peking University Press, 2016
独立核验依据 · Independent verification: 核验依据 2 ISBN 9787301272121（豆瓣书目条目: 基础有机化学）
#橡胶 #熵 #弹性
Flory-Huggins 相互作用参数 chi 随温度升高而减小时,聚合物溶液会出现哪种相分离行为,临界点如何确定?
When the Flory-Huggins interaction parameter chi decreases with increasing temperature, what phase-separation behavior appears in a polymer solution and how is the critical point determined?
chi 随温度降低(即升温使 chi 减小)时体系表现出上临界共溶温度(UCST)行为:高温均相,降温进入双结线以内发生液-液相分离。对高分子量链,混合熵项被链长 N 压低,临界点满足 chi_c ≈ (1/2)(1+1/√N)^2 并趋于 0.5,临界体积分数 φ_c ≈ 1/√N 且偏向溶剂一侧。这解释了为何高分子溶液的互溶窗口远比小分子混合物窄。
Such a system shows upper critical solution temperature (UCST) behavior: miscible at high temperature, it enters the binodal on cooling and undergoes liquid-liquid demixing. For long chains the entropy term is suppressed by the degree of polymerization N, giving chi_c ≈ (1/2)(1+1/√N)^2 → 0.5 and a critical polymer volume fraction φ_c ≈ 1/√N skewed toward solvent-rich compositions. This is why polymer solutions have far narrower miscibility windows than small-molecule mixtures.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-10-04
来源 · Source
P. J. Flory《Principles of Polymer Chemistry》(1953)第十二章格胞统计处理
P. J. Flory, Principles of Polymer Chemistry, Cornell University Press, 1953, Ch. XII lattice-statistical treatment
独立核验依据 · Independent verification: 核验依据 1 ISBN 978-0-8014-0134-3 (1953, Cornell)
#Flory-Huggins理论 #相分离
多数聚合物溶液降温才浑浊,聚N-异丙基丙烯酰胺的水溶液却在加热到32摄氏度附近突然分相,这是为什么?
Most polymer solutions cloud on cooling, yet aqueous poly(N-isopropylacrylamide) suddenly phase-separates when warmed past about 32 degrees Celsius — why?
Flory-Huggins相互作用参数并不是常数,它同时包含依赖温度的焓贡献与过量熵贡献;酰胺基团与水之间的氢键随升温削弱,熵项又不利于混合,χ随之越过临界值。混合自由能曲线因此失去稳定性,体系在下临界共溶温度处自发脱混。这一温敏特性让PNIPAM成为智能水凝胶与温控分离膜的骨架材料。
The Flory-Huggins interaction parameter is anything but constant: it carries both a temperature-dependent enthalpic part and an excess entropic part. Hydrogen bonds between amide groups and water weaken as heat is applied while the entropic term already disfavors mixing, so chi climbs past its critical value. The mixed free-energy curve then loses stability and demixes spontaneously at the lower critical solution temperature — the property that makes PNIPAM a scaffold for smart hydrogels and thermally gated membranes.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-10-04
来源 · Source
H. G. Schild《Poly(N-isopropylacrylamide): experiment, theory and application》,Progress in Polymer Science 17 (1992) 163
H. G. Schild, Poly(N-isopropylacrylamide): experiment, theory and application, Progress in Polymer Science 17 (1992) 163
独立核验依据 · Independent verification: 核验依据 1 DOI 10.1016/0079-6700(92)90023-r
#下临界共溶温度 #氢键作用
透明胶带为什么能粘东西又容易撕下？
Why does sticky tape adhere yet peel off cleanly?
胶层是黏弹性体，轻压即润湿贴合，靠内聚力和附着力抓住表面；撕拉时内部不断裂就能整片脱离。
The adhesive is viscoelastic: light pressure wets the surface, and cohesion plus adhesion hold it; peeling withdraws it intact without breaking.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-10-04
来源 · Source
Rosen & Kunjappu《表面活性剂与界面现象》（第4版），第1章
Rosen & Kunjappu, "Surfactants and Interfacial Phenomena" (4th ed.), Ch.1
独立核验依据 · Independent verification: 核验依据 1 ISBN 978-1-118-22902-6 (2012, Wiley)
#胶带 #黏弹性 #adhesive
凯夫拉为什么这么强？
Why is Kevlar so strong?
对位芳纶分子链刚性强、氢键片层规整取向，使强度与重量比极高，用于防弹。
Para-aramid chains are rigid with ordered hydrogen-bonded sheets, giving an extremely high strength-to-weight ratio used in body armor.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Brown, LeMay 等,《Chemistry: The Central Science》第14版,Pearson,2017
T. L. Brown et al., Chemistry: The Central Science, 14th ed., Pearson, 2017
#凯夫拉 #芳纶 #高强度
邻苯二甲酸二辛酯这类小分子增塑剂,为什么能让硬质PVC的玻璃化转变温度大幅下降?
How do small-molecule plasticizers such as dioctyl phthalate drive the glass transition temperature of rigid PVC so far downward?
增塑剂分子插入高分子链之间,既扩大了体系的自由体积,又屏蔽了链段间的偶极-偶极吸引,使链段在更低的温度下就能开始协同运动。Tg的降幅可按增塑剂体积分数用Kelley-Bueche方程估算。用量过头则因相分离而迁移渗出,制品会重新发脆。
Plasticizer molecules slip between the chains, enlarging the free volume while screening dipole-dipole attraction between segments, so cooperative segmental motion begins at a much lower temperature. The drop in Tg can be estimated from the plasticizer volume fraction with the Kelley-Bueche equation. Beyond an optimum dose the additive phase-separates and migrates out, leaving the product brittle again.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-10-04
来源 · Source
J. Brandrup 等《Polymer Handbook》第4版第VI章,Wiley-Interscience,1999
J. Brandrup et al., Polymer Handbook, 4th ed., Chapter VI, Wiley-Interscience, 1999
独立核验依据 · Independent verification: 核验依据 1 ISBN 9780471098041 (1999)
#玻璃化转变 #增塑机理
羊毛毛衣水洗后为什么会缩成一团？
Why does a wool sweater shrink into a ball when washed?
羊毛纤维表面有鳞片，热水加揉搓让鳞片互相勾住、纠结成毡，这种毡化不可逆。
Wool fibers have scales; hot water and agitation make the scales hook together into irreversible felt.
难度 进阶 · 适合 大众
CC BY 4.0 · 来源待核验 · Source pending review
来源 · Source
出处备注：本题原挂出处与答案内容不符，已撤回；具体书目待补，暂不展示来源。
本题原挂出处与答案内容不符，已撤回；具体书目待补。
Previous citation withdrawn as unsupported for this answer; a specific source is pending.
#羊毛 #毡化 #鳞片
白乳胶(木工胶)为什么能粘木头？
Why does white (PVA) wood glue stick wood?
它是聚醋酸乙烯乳液，水分蒸发后聚合物成膜并渗入木纤维孔隙，靠机械咬合加分子间力把木头粘牢。
It’s a polyvinyl acetate emulsion; as water evaporates the polymer films and penetrates wood pores, bonding by mechanical interlocking plus intermolecular forces.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-11-02
来源 · Source
潘祖仁《高分子化学》
Polymer Chemistry (Pan Zuren)
独立核验依据 · Independent verification: 核验依据 1 ISBN 9787122000248（豆瓣书目条目: 高分子化学）
#白乳胶 #PVA #木工胶
氨纶（莱卡）为什么能拉伸好几倍？
Why can spandex (Lycra) stretch several times?
它含软段与硬段嵌段，软段可卷曲拉伸、硬段固定位置帮助回弹，所以弹性极大。
It has soft and hard segments: soft segments coil and stretch while hard segments anchor and snap back, giving huge elasticity.
难度 入门 · 适合 小学高段(9-12)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Brown, LeMay 等,《Chemistry: The Central Science》第14版,Pearson,2017
T. L. Brown et al., Chemistry: The Central Science, 14th ed., Pearson, 2017
#氨纶 #弹性 #高分子
为什么塑料那么轻？
Why is plastic so light?
塑料是碳氢长链高分子，本身密度接近水甚至更小，所以同样体积比金属轻得多。
Plastics are long carbon-hydrogen polymer chains with densities near or below water, so they are far lighter than metals by volume.
难度 入门 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
邢其毅 等,《基础有机化学》第4版,北京大学出版社,2016
Xing Qiyi et al., Basic Organic Chemistry, 4th ed., Peking University Press, 2016
独立核验依据 · Independent verification: 核验依据 2 ISBN 9787301272121（豆瓣书目条目: 基础有机化学）
#塑料 #密度 #高分子
衣服为什么会起皱？
Why do clothes wrinkle?
棉花等纤维里的分子靠氢键连接，被折叠挤压后氢键重新排列，就留下折痕。
Fibers like cotton are held by hydrogen bonds; folding lets them re-form in new patterns, leaving creases.
难度 入门 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-11-02
来源 · Source
潘祖仁《高分子化学》
Polymer Chemistry (Pan Zuren)
独立核验依据 · Independent verification: 核验依据 1 ISBN 9787122000248（豆瓣书目条目: 高分子化学）
#衣物 #氢键 #褶皱