熱泳

熱泳，也稱為熱泳法或索瑞特效應，是溫度梯度對顆粒產生的效應，造成它們從一個熱板移動至低溫區。该现象倾向于将轻分子移动到高温区域，将重分子移动到低温区域。术语“热泳”最常用于平均自由程 $\lambda$ 与其特征长度尺度 $L$ 相当的气溶胶混合物，但也常常指所有物相中的该现象。术语“索瑞特效应”通常用于液体混合物。這種效應在行星分化中有重大的作用，在光纖的製造中更是功績顯赫。

在日常生活中最明显的例子是靠近暖气的墙面会发黑，这是因为墙面温度较低，与暖气产生温度梯度，空气中的颗粒因而碰撞到墙面而被吸附。

热泳作用力

该现象在约一毫米或更小尺度上观察到。一个可用肉眼在良好光照下看到的例子是：当电暖器的发热棒周围有烟雾时，烟雾会远离发热棒。靠近发热棒的空气小粒子被加热后沿温度梯度向外快速流动。尽管在相同温度下粒子的动能相近，轻粒子获得的速度比重粒子更高。当它们与烟雾中较大且较慢的粒子碰撞时，会把这些较大粒子自发热棒处推开。把烟雾粒子从发热棒推开的力就是热泳力的一个例子。在环境条件下，空气的平均自由程约为68 nm，而相关的特征长度尺度在100-1000 nm之间。

当粒子从热区移动到冷区时，热扩散被称为“正（positive）”；反向则称为“负（negative）”。通常混合物中较重或较大的组分表现为正向热泳，而较轻或较小的组分表现为负向。除粒子尺寸和温度梯度陡峭程度外，粒子的热导率和吸热性也起作用。Braun等人提出分子水合壳的电荷和熵对水溶液中生物分子的热泳起主要作用。

定量描述为：

${\frac {\partial \chi }{\partial t}}=\nabla \cdot (D\,\nabla \chi +D_{T}\,\chi (1-\chi )\,\nabla T)$

其中 $\chi$ 为粒子浓度， $D$ 为扩散系数， $D_{T}$ 为热扩散系数。两者之比

$S_{T}={\frac {D_{T}}{D}}$

称为索瑞特系数。

热泳因子已根据已知分子模型由分子相互作用势计算得出。

应用

热泳力有多种实际应用。应用的基础是不同粒子在温度梯度作用下迁移不同。混合后可用该力分离不同粒子；已分离的粒子可用该力防止再混合。

杂质离子可能从半导体晶圆的冷侧迁移到热侧，因为较高温度使得原子跃迁所需的过渡结构更易实现。扩散通量可沿或逆温度梯度方向，取决于所涉材料。热泳力已在商业静电除尘器中用于类似用途。它利用于光纤制造的真空沉积（英语：Vacuum deposition）过程中。它可作为污垢沉积（fouling）中的重要传输机制。热泳也被证明可用于药物发现，通过比较目标分子结合与未结合时的运动来检测適體结合。该方法被称为微尺度热泳（英语：Microscale thermophoresis）。热泳已被展示为操作单个生物大分子（如基因组尺度DNA和HIV病毒）的一种多用途技术，通常在微纳通道中通过光诱导的局部加热实现。此外，热泳是用于在場流分離中分离不同聚合物颗粒的方法之一。

历史

气体混合物中的热泳最早由约翰·丁达尔于1870年观察并报告，1882年由約翰·斯特拉特进一步阐明。液体混合物中的热泳最早由卡尔·路德维希于1856年观察并报告，1879年由查尔斯·索瑞特（英语：Charles Soret）进一步研究。

詹姆斯·克拉克·麦克斯韦在1873年关于不同类型分子混合（这也可包括比分子更大的微粒）的论述中写道：

“扩散这一过程……发生在气体、液体甚至某些固体中……动力学理论也告诉我们，如果不同质量的分子互相碰撞会发生什么。较大的质量运动更慢，较小的质量运动更快，因此平均而言，每个分子无论大小将具有相同的运动能量。我主张优先证明的这一动力学定理最近已被玻尔兹曼博士大大发展和改进。”

该现象曾被西德尼·查普曼在理论上分析。

固体界面的热泳于2006年由Schoen等人在数值上发现，并由Barreiro等人在实验上证实。

流体中的负热泳最早在1967年由Dwyer在一个理论解中注意到，术语“负热泳”由Sone提出。固体界面的负热泳首次由Leng等人在2016年观察到。

參考

Stefan Duhr, and Dieter Braun. Why molecules move along a temperature gradient. PNAS. 2006, 103: 19678–19682. [1] （页面存档备份，存于互联网档案馆）
术语在线. www.termonline.cn. [2025-09-13].
Talbot L, Cheng RK, Schefer RW, Willis DR. Thermophoresis of particles in a heated boundary layer (PDF). J. Fluid Mech. 1980, 101 (4): 737–758 [2025-09-13]. Bibcode:1980JFM...101..737T. doi:10.1017/S0022112080001905. （原始内容存档 (PDF)于2024-03-24）.
Jennings, S. The mean free path in air. Journal of Aerosol Science. 1988, 19 (2): 159–166. Bibcode:1988JAerS..19..159J. doi:10.1016/0021-8502(88)90219-4.
Keith CH, Derrick JC. Measurement of the particle size distribution and concentration of cigarette smoke by the "conifuge". Journal of Colloid Science. April 1960, 15 (4): 340–356. doi:10.1016/0095-8522(60)90037-4.
Duhr S, Braun D. Why molecules move along a temperature gradient. Proc. Natl. Acad. Sci. U.S.A. December 2006, 103 (52): 19678–19682. Bibcode:2006PNAS..10319678D. PMC 1750914 . PMID 17164337. doi:10.1073/pnas.0603873103 .
Reineck P, Wienken CJ, Braun D. Thermophoresis of single stranded DNA. Electrophoresis. January 2010, 31 (2): 279–286. PMID 20084627. S2CID 36614196. doi:10.1002/elps.200900505.
J. Chem. Phys., 50, 4886, (1960)
Baaske P, Wienken CJ, Reineck P, Duhr S, Braun D. Optical Thermophoresis for Quantifying the Buffer Dependence of Aptamer Binding. Angewandte Chemie International Edition. February 2010, 49 (12): 2238–2241. PMID 20186894. S2CID 42489892. doi:10.1002/anie.200903998.
- A hot road to new drugs. Phys.org. February 24, 2010 [2025-09-13]. （原始内容存档于2016-03-07）.
Wienken CJ, et al. Protein-binding assays in biological liquids using microscale thermophoresis. Nature Communications. 2010, 1 (7): 100. Bibcode:2010NatCo...1..100W. PMID 20981028. doi:10.1038/ncomms1093 .
An illustration of a device based on microscale thermophoresis at NanoTemper.de （页面存档备份，存于互联网档案馆）
Zhao, Chao; Oztekin, Alparslan; Cheng, Xuanhong. Measuring the thermal diffusion coefficients of artificial and biological particles in a microfluidic chip. Bulletin of the American Physical Society. 24 Nov 2013, 58 [7 April 2015]. Bibcode:2013APS..DFD.D6002Z. （原始内容存档于2025-01-23）.
Zhao, Chao; Fu, Jinxin; Oztekin, Alparslan; Cheng, Xuanhong. Measuring the Soret coefficient of nanoparticles in a dilute suspension. Journal of Nanoparticle Research. 1 Oct 2014, 16 (10): 2625. Bibcode:2014JNR....16.2625Z. PMC 4160128 . PMID 25221433. doi:10.1007/s11051-014-2625-6.
Thamdrup LH, Larsen NB, Kristensen A. Light-Induced Local Heating for Thermophoretic Manipulation of DNA in Polymer Micro- and Nanochannels. Nano Letters. February 2010, 10 (3): 826–832. Bibcode:2010NanoL..10..826T. PMID 20166745. doi:10.1021/nl903190q. ^{[失效連結]}
An illustration of a Thermal Field Flow Fractionation Machine based on thermophoresis used to separate mixed polymers at Postnova.com 互联网档案馆的存檔，存档日期2018-12-22.
A brief history of thermophoresis studies is in Encyclopedia of Surface And Colloid Science, Volume 2, published by Taylor & Francis, year 2006. John Tyndall's original article in year 1870 is online at Archive.org.
"Molecules" by James Clerk Maxwell, published in September 1873 in Nature (magazine). Reproduced online at Victorianweb.org （页面存档备份，存于互联网档案馆）.
Schoen, Philipp A. E.; Walther, Jens H.; Arcidiacono, Salvatore; Poulikakos, Dimos; Koumoutsakos, Petros. Nanoparticle Traffic on Helical Tracks: Thermophoretic Mass Transport through Carbon Nanotubes. Nano Letters. 2006-09-01, 6 (9): 1910–1917. Bibcode:2006NanoL...6.1910S. ISSN 1530-6984. PMID 16968000. S2CID 29154934. doi:10.1021/nl060982r.
Barreiro, Amelia; Rurali, Riccardo; Hernández, Eduardo R.; Moser, Joel; Pichler, Thomas; Forró, László; Bachtold, Adrian. Subnanometer motion of cargoes driven by thermal gradients along carbon nanotubes. Science. 2008-05-09, 320 (5877): 775–778. Bibcode:2008Sci...320..775B. ISSN 1095-9203. PMID 18403675. S2CID 6026906. doi:10.1126/science.1155559 .
Dwyer, Harry A. Thirteen-Moment Theory of the Thermal Force on a Spherical Particle. Physics of Fluids. 1967-05-01, 10 (5): 976–984. Bibcode:1967PhFl...10..976D. ISSN 0031-9171. doi:10.1063/1.1762250.
Sone, Yoshio. A Flow Induced by Thermal Stress in Rarefied Gas. Journal of the Physical Society of Japan. 1972-07-15, 33 (1): 232–236. Bibcode:1972JPSJ...33..232S. ISSN 0031-9015. doi:10.1143/JPSJ.33.232.
Leng, Jiantao; Guo, Zhengrong; Zhang, Hongwei; Chang, Tienchong; Guo, Xingming; Gao, Huajian. Negative Thermophoresis in Concentric Carbon Nanotube Nanodevices. Nano Letters. 2016-10-12, 16 (10): 6396–6402. Bibcode:2016NanoL..16.6396L. ISSN 1530-6984. PMID 27626825. doi:10.1021/acs.nanolett.6b02815.

这是一篇与热力学相关的小作品。您可以通过编辑或修订扩充其内容。

[1] Stefan Duhr, and Dieter Braun. Why molecules move along a temperature gradient. PNAS. 2006, 103: 19678–19682. [1] （页面存档备份，存于互联网档案馆）

[2] 术语在线. www.termonline.cn. [2025-09-13].

[Talbot-3] Talbot L, Cheng RK, Schefer RW, Willis DR. Thermophoresis of particles in a heated boundary layer (PDF). J. Fluid Mech. 1980, 101 (4): 737–758 [2025-09-13]. Bibcode:1980JFM...101..737T. doi:10.1017/S0022112080001905. （原始内容存档 (PDF)于2024-03-24）.

[Jennings2-4] Jennings, S. The mean free path in air. Journal of Aerosol Science. 1988, 19 (2): 159–166. Bibcode:1988JAerS..19..159J. doi:10.1016/0021-8502(88)90219-4.

[Keith2-5] Keith CH, Derrick JC. Measurement of the particle size distribution and concentration of cigarette smoke by the "conifuge". Journal of Colloid Science. April 1960, 15 (4): 340–356. doi:10.1016/0095-8522(60)90037-4.

[Duhr12-6] Duhr S, Braun D. Why molecules move along a temperature gradient. Proc. Natl. Acad. Sci. U.S.A. December 2006, 103 (52): 19678–19682. Bibcode:2006PNAS..10319678D. PMC 1750914 . PMID 17164337. doi:10.1073/pnas.0603873103 .

[Reineck2-7] Reineck P, Wienken CJ, Braun D. Thermophoresis of single stranded DNA. Electrophoresis. January 2010, 31 (2): 279–286. PMID 20084627. S2CID 36614196. doi:10.1002/elps.200900505.

[8] J. Chem. Phys., 50, 4886, (1960)

[9] Baaske P, Wienken CJ, Reineck P, Duhr S, Braun D. Optical Thermophoresis for Quantifying the Buffer Dependence of Aptamer Binding. Angewandte Chemie International Edition. February 2010, 49 (12): 2238–2241. PMID 20186894. S2CID 42489892. doi:10.1002/anie.200903998.
A hot road to new drugs. Phys.org. February 24, 2010 [2025-09-13]. （原始内容存档于2016-03-07）.

[10] A hot road to new drugs. Phys.org. February 24, 2010 [2025-09-13]. （原始内容存档于2016-03-07）.

[Wienken-10] Wienken CJ, et al. Protein-binding assays in biological liquids using microscale thermophoresis. Nature Communications. 2010, 1 (7): 100. Bibcode:2010NatCo...1..100W. PMID 20981028. doi:10.1038/ncomms1093 .

[11] An illustration of a device based on microscale thermophoresis at NanoTemper.de （页面存档备份，存于互联网档案馆）

[12] Zhao, Chao; Oztekin, Alparslan; Cheng, Xuanhong. Measuring the thermal diffusion coefficients of artificial and biological particles in a microfluidic chip. Bulletin of the American Physical Society. 24 Nov 2013, 58 [7 April 2015]. Bibcode:2013APS..DFD.D6002Z. （原始内容存档于2025-01-23）.

[13] Zhao, Chao; Fu, Jinxin; Oztekin, Alparslan; Cheng, Xuanhong. Measuring the Soret coefficient of nanoparticles in a dilute suspension. Journal of Nanoparticle Research. 1 Oct 2014, 16 (10): 2625. Bibcode:2014JNR....16.2625Z. PMC 4160128 . PMID 25221433. doi:10.1007/s11051-014-2625-6.

[14] Thamdrup LH, Larsen NB, Kristensen A. Light-Induced Local Heating for Thermophoretic Manipulation of DNA in Polymer Micro- and Nanochannels. Nano Letters. February 2010, 10 (3): 826–832. Bibcode:2010NanoL..10..826T. PMID 20166745. doi:10.1021/nl903190q. ^{[失效連結]}

[15] An illustration of a Thermal Field Flow Fractionation Machine based on thermophoresis used to separate mixed polymers at Postnova.com 互联网档案馆的存檔，存档日期2018-12-22.

[16] A brief history of thermophoresis studies is in Encyclopedia of Surface And Colloid Science, Volume 2, published by Taylor & Francis, year 2006. John Tyndall's original article in year 1870 is online at Archive.org.

[17] "Molecules" by James Clerk Maxwell, published in September 1873 in Nature (magazine). Reproduced online at Victorianweb.org （页面存档备份，存于互联网档案馆）.

[18] Schoen, Philipp A. E.; Walther, Jens H.; Arcidiacono, Salvatore; Poulikakos, Dimos; Koumoutsakos, Petros. Nanoparticle Traffic on Helical Tracks: Thermophoretic Mass Transport through Carbon Nanotubes. Nano Letters. 2006-09-01, 6 (9): 1910–1917. Bibcode:2006NanoL...6.1910S. ISSN 1530-6984. PMID 16968000. S2CID 29154934. doi:10.1021/nl060982r.

[19] Barreiro, Amelia; Rurali, Riccardo; Hernández, Eduardo R.; Moser, Joel; Pichler, Thomas; Forró, László; Bachtold, Adrian. Subnanometer motion of cargoes driven by thermal gradients along carbon nanotubes. Science. 2008-05-09, 320 (5877): 775–778. Bibcode:2008Sci...320..775B. ISSN 1095-9203. PMID 18403675. S2CID 6026906. doi:10.1126/science.1155559 .

[20] Dwyer, Harry A. Thirteen-Moment Theory of the Thermal Force on a Spherical Particle. Physics of Fluids. 1967-05-01, 10 (5): 976–984. Bibcode:1967PhFl...10..976D. ISSN 0031-9171. doi:10.1063/1.1762250.

[21] Sone, Yoshio. A Flow Induced by Thermal Stress in Rarefied Gas. Journal of the Physical Society of Japan. 1972-07-15, 33 (1): 232–236. Bibcode:1972JPSJ...33..232S. ISSN 0031-9015. doi:10.1143/JPSJ.33.232.

[22] Leng, Jiantao; Guo, Zhengrong; Zhang, Hongwei; Chang, Tienchong; Guo, Xingming; Gao, Huajian. Negative Thermophoresis in Concentric Carbon Nanotube Nanodevices. Nano Letters. 2016-10-12, 16 (10): 6396–6402. Bibcode:2016NanoL..16.6396L. ISSN 1530-6984. PMID 27626825. doi:10.1021/acs.nanolett.6b02815.