Video Experimental Relacionado
Updated: Jun 21, 2026
08:59
Dry Oxidation and Vacuum Annealing Treatments for Tuning the Wetting Properties of Carbon Nanotube Arrays
Published on: April 15, 2013
Conducción de agua a través del canal hidrofóbico de un nanotubo de carbono
G Hummer1, J C Rasaiah, J P Noworyta
1Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0520, USA. hummer@helix.nih.gov
Nature
|November 9, 2001
Resumen
Las moléculas de agua forman espontáneamente cadenas ordenadas dentro de los nanotubos de carbono, exhibiendo un flujo en forma de pulso. Los cambios en la polaridad de los nanotubos alteran drásticamente el llenado de agua, lo que sugiere canales moleculares sintonizables para el transporte de agua y protones.
Área de la Ciencia:
- La ciencia a nanoescala es una ciencia a nanoescala.
- Química física es la química física de las cosas.
- Ciencia de los materiales ciencia de los materiales.
Sus antecedentes:
- El confinamiento a nanoescala puede alterar las propiedades del material, induciendo transiciones de fase ausentes en los sistemas a granel.
- Las moléculas de agua exhiben fuertes enlaces de hidrógeno, lo que lleva a fenómenos como las transiciones de secado en escalas nanométricas cuando interactúan con superficies no polares.
Objetivo del estudio:
- Para investigar el comportamiento del agua confinada dentro de nanotubos de carbono no polares.
- Para explorar la dinámica de la formación de la cadena de agua y el transporte bajo confinamiento.
- Para comprender el impacto de las interacciones superficiales en la hidratación de los poros del agua.
Principales métodos:
- Se emplearon simulaciones de dinámica molecular para modelar el comportamiento del agua en nanotubos de carbono.
- Las simulaciones analizaron el llenado espontáneo y la transmisión de moléculas de agua a través del nanotubo.
- Se investigó el efecto de variar la atracción de la pared del nanotubo por el agua.
Principales resultados:
- Se observó el llenado espontáneo y continuo de un nanotubo de carbono no polar por una cadena de agua ordenada en una dimensión.
- La transmisión de agua en forma de pulso a través del nanotubo se produjo debido a un movimiento concertado impulsado por la unión de hidrógeno.
- Una ligera disminución en la atracción del agua del tubo indujo fuertes transiciones de dos estados entre los estados de poro vacío y lleno en una escala de tiempo de nanosegundos.
Conclusiones:
- Los nanotubos de carbono pueden actuar como canales moleculares únicos para el agua y los protones debido a su estructura rígida y no polar.
- La ocupación y la conductividad de estos canales de nanotubos son ajustables mediante la alteración de la polaridad local y las condiciones del disolvente.
- Estos hallazgos sugieren aplicaciones potenciales en el transporte molecular y las tecnologías de separación.
Más Videos Relacionados
Videos de Conceptos Relacionados
01:19Ion Channels
The movement of ions like sodium, potassium, and calcium into and out of the cell is essential to maintain the electrochemical gradient in living cells. The ion channels—a class of membrane transport proteins—help maintain this ionic gradient for the smooth functioning of physiological activities such as maintaining cell size and volume, conducting nerve impulses, and gas and nutrient exchange.
Ion channels are specialized integral membrane proteins on the plasma membrane that allow specific...
Ion channels are specialized integral membrane proteins on the plasma membrane that allow specific...
01:19Facilitated Transport
The chemical and physical properties of plasma membranes cause them to be selectively permeable. Since plasma membranes have both hydrophobic and hydrophilic regions, substances need to be able to transverse both regions. The hydrophobic area of membranes repels substances such as charged ions. Therefore, such substances need special membrane proteins to cross a membrane successfully. In facilitated transport, also known as facilitated diffusion, molecules and ions travel across a membrane via...
01:13Electrical Conductivity
In perfect conductors, the electric field inside is always zero due to the abundance of free electrons, which nullify any field by flowing. As a result, any residual charge resides on the surface.
In a practical conductor, an applied electric field may be sustained, causing a flow of electrons, which produce a current. The differential form of the current, the current density, is related to the electric field.
More generally, it is related to the force per unit charge, which involves the...
In a practical conductor, an applied electric field may be sustained, causing a flow of electrons, which produce a current. The differential form of the current, the current density, is related to the electric field.
More generally, it is related to the force per unit charge, which involves the...
01:21Electrochemical Gradient and Channel Proteins: An Overview
An electrochemical gradient is a fundamental concept in biology and chemistry. It regulates the movement of ions across cell membranes. This movement is influenced by two factors:
The electrical gradient: The electrical gradient across cell membranes refers to the difference in electric charge between the inside and outside of a cell. This difference drives the movement of ions towards or away from the cells. For instance, if the inside of the cell is more negatively charged relative to the...
The electrical gradient: The electrical gradient across cell membranes refers to the difference in electric charge between the inside and outside of a cell. This difference drives the movement of ions towards or away from the cells. For instance, if the inside of the cell is more negatively charged relative to the...
01:26Regulation of Water Output
The human body predominantly expels water through the urinary system. On average, an individual generates around 1.5 liters of urine each day. This amount can fluctuate based on how well a person is hydrated, but a critical minimum quantity of urine must be produced to ensure the body's proper functioning. Daily, the kidneys remove 600 to 1200 milliosmoles of dissolved substances, effectively excreting excess minerals and water-soluble toxins such as creatinine, urea, and uric acid from the...
01:14Testing Water Quality
When the quality of water for concrete preparation is uncertain, its impact on the setting time of cement and compressive strength of mortar is assessed by comparison with de-ionized or distilled water benchmarks. American Society for Testing and Materials (ASTM) C1602 requires the setting times to be within 90 minutes of the control, British Standard (BS) 3146:1980 allows a 30-minute variance in the initial setting, while British Standards European Norm (BS EN) 1008 specifies initial setting...