Slide vật liệu nano và màng mỏng microfkuidic devices

.c om du o ng th an co ng Microfluidic Devices cu u Thuy N.T Nguyen CuuDuongThanCong.com https://fb.com/tailieudientucntt Contents co an th ng u Sensor du o Pump Valve Mixer Channel Reactor ng c om Introduction Components of microfluidic devices cu Structure of Microfluidic device Design Structure and Fabrication Application CuuDuongThanCong.com https://fb.com/tailieudientucntt Introduction cu u du o ng th an co ng c om • Total analysis system (TAS): was first introduced in 1980s for analysis in chemical as well as biochemica l • Micro total analysis system (µTAS): was first develop ed in 1990s µTAS combines microfluidics, mechanic al actuators, and transducers for complete analysis i n micro chip ã Now àTAS was broaden to synthesize and other app lication In general, it was known as Microfluidic devi ce or Lab on a chip devices CuuDuongThanCong.com https://fb.com/tailieudientucntt Microvalve Depend on the strength of fl ow, we have stiffness of flap an co ng c om • Passive valve (check valve): no actuation for control, unidirectional flow ng th flow cu u du o • Active valve: require an actuator to provide a mechanical action The actuation include piezoelectric, electrostatic, electromagnetic, pneumatic, thermopneumatic actuation, bistable, phase-change CuuDuongThanCong.com https://fb.com/tailieudientucntt Microvalve Electric: static, piezo Magnetic Thermal expansion Ultrasonic Design c om Flow rate (velocity, dimension)  size of valve  stiffness of memb rane relate to material, dimension  deflection  applied force  c hoice the actuation Actuator ng Controller an co Actuation u In micro fluidic: du o ng th membrane cu Membrane: silicon or glass ( often 50 µm thickness, 2mm x 2mm), sometimes poly mer Glass/silicon were wet etching by HF/KOH or dry etching Then they were anodic bonding CuuDuongThanCong.com https://fb.com/tailieudientucntt .c om ng co an th ng du o u cu CuuDuongThanCong.com https://fb.com/tailieudientucntt .c om ng co an th ng du o u cu CuuDuongThanCong.com https://fb.com/tailieudientucntt .c om ng co an th ng du o u cu CuuDuongThanCong.com https://fb.com/tailieudientucntt .c om ng co an th ng du o u cu CuuDuongThanCong.com https://fb.com/tailieudientucntt .c om ng co an th ng du o u cu Bistable valve 10 CuuDuongThanCong.com https://fb.com/tailieudientucntt J Micromech Microeng 12 (2002) 420-424 PZT: 6x6 mm2, 250 um thickness (PZT-5H plate from Morgan Matroc Ltd) an co ng c om Si membrane: 7mm x 7mm x 70um th Valve u 0.6 mm cu 12mm du o ng Bonding PZT glued with Si m embrane by conduct ive epoxy 12mm 18 CuuDuongThanCong.com https://fb.com/tailieudientucntt .c om ng co cu u du o ng th an Pump connect power Test with ethanol, pump rate maxim um 1500 µl/min at 2.5kHz, with bac kpressure 1000 Pa Real measurement difference simul ation because of: - hydrodynamic phenomena 19 CuuDuongThanCong.com https://fb.com/tailieudientucntt Flow transport by pressure/electrickinetic c om Pressure driven flow: parabolic profile velocity due to visc osity th an co ng Electric-osmotic flow have band broadening due to induced pressure gradient ng Profile pressure  RT du o cu u D  Journal of Colloid and Interface Science 275 (2004) 670–678 2 2F z c  eo   o  R: universal gas constant T: absolute temperature F: Faraday constant z: charge number Schematic of electric d ouble layer model v eo   eo E c: concentration ε: dielectric constant 20 CuuDuongThanCong.com https://fb.com/tailieudientucntt Characteristics of fluid in micro scale c om Affected Force: capillary force (because of surface tension) inst ead of inertia in macro flow co ng F cap   r  cos  du o ng th an Viscosity is significant effect High interface to volume ratio: interaction between liquid an surf ace wall is strong  high fluidic resistance The smaller channel si ze, the bigger fluidic resistance cu u With circular cross s ection resis  8 L R R: channel radius L: channel length η: viscosity 21 CuuDuongThanCong.com https://fb.com/tailieudientucntt Mixer and channel Mixer: to attain a homogeneous of two solutions in as little time as c om possible • Passive mixer: only base on diffusion (internal energy) cu u du o ng th an co ng • Active mixer: use external energy to induce turbulence 22 CuuDuongThanCong.com https://fb.com/tailieudientucntt Mixer and channel c om How to improve the mixing? Passive mixer: Reduce diffusion distance  reduce time according to Einstein-Smoluchowski equation ng Split channel into an array of smaller channels  to increase the contact areas an co Form groove across the channel or block for change direction flow  induce turbulence th x  Dt t: diffusion time D: diffusion coefficient du o ng E-S equation x: diffusion distance cu u Active mixer: Applied voltage across the mixing chamber Used pump to make bubble 23 CuuDuongThanCong.com https://fb.com/tailieudientucntt Sensor ng c om In microfluidic, we need to measure Flow rate (pressure, velocity)  mechanical sensor (Piezoresistive or cap acitive) Temperature of flow  temperature sensor Concentration of solution  optical sensor th an co Piezoresistive pressure sensor pressure (resistor) cu Sensitive element u (membrane) + du o ng Elastic element Polysilicon (0.5um) was d Wheatstone bridge eposited, doped Voltage 24 CuuDuongThanCong.com https://fb.com/tailieudientucntt Micro Total Analysis System (μ_TAS) c om  To design a µ_TAS, we must answer for What is purpose o f device? Which is the fluid concern? co ng  Whether in chemical or in biology, device must be inert or c ompatible with fluid + reactor u preparation Mixer / du o Sample ng th an Common components of µ_TAS cu Injection (discrete/ co ntinuous) Filter + Separation + Detection Electrophoresis Mechanical Chromatography Electrical Mass spectrocopy optical 25 CuuDuongThanCong.com https://fb.com/tailieudientucntt ng co cu u du o ng th an • Mechanical sensing – Mass sensing – Stress sensing • Optical sensing - Fluorescence - Luminescence • Electrochemical sensing – Potentiometric – Conductometric – Amperometer c om Sensing mechanism 26 CuuDuongThanCong.com https://fb.com/tailieudientucntt Mechanical sensing Stress sensing cu u du o ng th an co ng c om Mass sensing 27 CuuDuongThanCong.com https://fb.com/tailieudientucntt Electrochemical sensing Anode Cathode B + e- c om C h e m ica l E n erg y , G a lv a n ic E le c tric a l E ne rgy, C he m ic a l T nsform a tion A+ + e- A E le c tric a l S igna l E le c tro ly tic ng A + B Oxidized BA+ + B- Reduced Electron acceptor Reducing agent Oxidizing agent an co Electron donor UG n+ p-Si cu n+ u du o ng th Potentionmetric: measure the oxidation/reduction potential UD Ion selective field effect transistor (ISFET) 28 CuuDuongThanCong.com https://fb.com/tailieudientucntt Optical sensing ng co hc  th an E  c om Fluorescence: measure the different w avelength between incident and em ission ligh  energy cu u du o ng Luminescence: measure the different optical power according Lambert Beer Law  concentration A ( c )  log( P solvent ) Pc 29 CuuDuongThanCong.com https://fb.com/tailieudientucntt .c om Capillary Electrophoresis (CE) co ng CE: to separate ionic species due to their frictional forces an d charge under electric field (base on their size to charge ratio) cu u du o ng th an CE use gel electrophoresis (agaro) to make different size por t and fluorescent dye for detection This method only detect the liquid have mobility and just show the size of sp ecies 30 CuuDuongThanCong.com https://fb.com/tailieudientucntt Chromatography c om Chromatography: techniques separation of complex mixtures rely on differential affinities of substance co ng Column chromatography: mixture is mobile in the capillary which have stati onary adsorbing such as paper, gelatin, magnesia on the surface an • Gas th • Liquid ng • Gel permeation du o Thin layer and paper chromatography cu u This method can separate almost liquid 31 CuuDuongThanCong.com https://fb.com/tailieudientucntt .c om Micro Total Analysis System (μ_TAS) cu u du o ng th an co ng Now μ_TAS is widely applied in many fields: Medicine-Biology : clinical diagnose, drug analysis Chemistry: chemical compound analysis Environment: water, air analysis Military: explosive detector Food,forensic analysis 32 CuuDuongThanCong.com https://fb.com/tailieudientucntt ... u Sensor du o Pump Valve Mixer Channel Reactor ng c om Introduction Components of microfluidic devices cu Structure of Microfluidic device Design Structure and Fabrication Application CuuDuongThanCong.com... synthesize and other app lication In general, it was known as Microfluidic devi ce or Lab on a chip devices CuuDuongThanCong.com https://fb.com/tailieudientucntt Microvalve Depend on the strength