Academic literature on the topic 'Poly Di-Methyl Siloxane'

A series of BCB-siloxane polymers with benzocyclobutene (BCB) pendant groups and polysiloxane mainchain was prepared by the hydrosilylation reaction between 4-(1,1-di-methyl-1-vinyl) silylbenzocyclobutene (4-DMVSBCB) and poly (methylhydrosiloxane) (PHMS) employing Pt/C as catalyst. Upon heating the BCB-siloxane polymers, the cross-linking occurred via ring-opening of benzocyclobutene as evidenced by on-line FT-IR, 1H NMR and 13C NMR. TGA examination indicates that the thermal stability was enhanced with increasing the incorporation ratio of BCB. Most importantly, the initial decomposition temperature of crosslinked BCB-siloxane resins is as high as 429 oC, showing a superior thermal resistance over most other BCB resins.

This paper demonstrates the potential for recovering dissolved methane from low temperature anaerobic processes treating domestic wastewater. In the absence of methane recovery, ca. 45% of the produced methane is released as a fugitive emission which results in a net carbon footprint of −0.47 kg CO2e m−3. A poly-di-methyl-siloxane (PDMS) membrane contactor was applied to support sweep gas desorption of dissolved methane using nitrogen. The dense membrane structure controlled gaseous mass transfer thus recovery was maximised at low liquid velocities. At the lowest liquid velocity, VL, of 0.0025 m s−1, 72% of the dissolved methane was recovered. A vacuum was also trialled as an alternative to sweep-gas operation. At vacuum pressures below 30 mbar, reasonable methane recovery was observed at an intermediate VL of 0.0056 m s−1. Results from this study demonstrate that dissolved methane recovery could increase net electrical production from low temperature anaerobic processes by ca. +0.043 kWhe m−3 and reduce the net carbon footprint to +0.01 kg CO2e m−3. However, further experimental work to optimise the gas-side hydrodynamics is required as well as validation of the long-term impacts of biofouling on process performance.

This paper present the results of (experiments and models) biosynthesized prodigiosin (PG) released from an implantable biomedical device on the viability of cancer cells. The implantable biomedical devices were obtained from poly-di-methyl-siloxane (PDMS) packages with well-controlled micro-channels and drug storage compartments, along with a drug storing polymer core (which contains thermosensitive Poly (N-isopropylacrylamide)(PNIPA)-based gels). The results were compared with drugs elution from devices loaded with paclitaxelTM. The effects of localized release of PG and paclitaxel (PTx) on cell viability were elucidated via clonogenic assay testing on MDA-MB-231 breast cancer cell line. The effects of PG and PTx released were also tested over a range of temperatures (37-45 ̊C) in which localized hyperthermia is applicable. The trends in the results were analysed using statistical models before discussion their implications for localized treatment of breast cancer.

AbstractTransmission electron microscopy (TEM) and focused ion beam (FIB) are proven tools to produce site-specific samples in which to study devices from initial processing to causes for failure, as well as investigating the quality, defects, interface layers, etc. However, the use of polymer substrates presents new challenges, in the preparation of suitable site-specific TEM samples, which include sample warping, heating, charging, and melting. In addition to current options that address some of these problems such as cryo FIB, we add an alternative method and FIB sample geometry that address these challenges and produce viable samples suitable for TEM elemental analysis. The key feature to this approach is a larger than usual lift-out block into which small viewing windows are thinned. Significant largely unthinned regions of the block are left between and at the base of the thinned windows. These large unthinned regions supply structural support and thermal reservoirs during the thinning process. As proof-of-concept of this sample preparation method, we also present TEM elemental analysis of various thin metallic films deposited on patterned polycarbonate, lacquer, and poly-di-methyl-siloxane substrates where the pattern (from low- to high-aspect ratio) is preserved.

Although wearable antennas have made great progress in recent years, how to design high-performance antennas suitable for most wireless communication systems has always been the direction of RF workers. In this paper, a new approach for the design and manufacture of a compact, low-profile, broadband, omni-directional and conformal antenna is presented, including the use of a customized flexible dielectric substrate with high permittivity and low loss tangent to realize the compact sensing antenna. Poly-di-methyl-siloxane (PDMS) is doped a certain proportion of aluminum trioxide (Al2O3) and Poly-tetra-fluoro-ethylene (PTFE) to investigate the effect of dielectric constant and loss tangent. Through a large number of comparative experiments, data on different doping ratios show that the new doped materials are flexible enough to increase dielectric constant, reduce loss tangent and significantly improve the load resistance capacity. The antenna is configured with a multisection microstrip stepped impedance resonator structure (SIR) to expand the bandwidth. The measured reflection return loss (S11) showed an operating frequency band from 0.99 to 9.41 GHz, with a band ratio of 146%. The antenna covers two important frequency bands, 1.71–2.484 GHz (personal communication system and wireless body area network (WBAN) systems) and 5.15–5.825 GHz (wireless local area network-WLAN)]. It also passed the SAR test for human safety. Therefore, the proposed antenna offers a good chance for full coverage of WLAN and large-scale development of wearable products. It also has potential applications in communication systems, wireless energy acquisition systems and other wireless systems.

Introduction: Organ-on-a-chip models are becoming popular due to its success in modeling human tissues and organs, to mimic human physiology and understand how diseases or drugs affect organs. Traditional 2-dimensional in vitro models are limited in recreating complicated bone structure and examining cell-cell interactions. Alternatively, bone-on-a-chip models establish biomimetic conditions to accurately recapitulate the complexity of the bone. However, bone-on-a-chip models as 3D culture systems do not accurately replicate the bone microenvironment. Rather, microfluidic devices allow for fluid control on a microscale or nanoscale level and the incorporation of fluid shear stress normally experienced by bone cells. The goal of this review paper is to summarize advancements to bone-on-a-chip models. Methods: Relevant articles were selected through a computerized search using GEOBASE and PubMED. Search terms included ‘microfluidic devices AND bones’, ‘organ-on-a-chip models’, ‘bone-on-a-chip models’, ‘PDMS AND bone regeneration’, ‘PolyHIPE AND bone regeneration’ and ‘bone scaffolds’. Results: Microfluidic chips are fabricated using soft lithography and poly-di-methyl siloxane (PDMS) which is a biocompatible, synthetic polymer that is used as a cell culture substrate but is too stiff to facilitate bone regeneration. Hydroxyapatite (HA), lined with PDMS, is commonly used, but the substrate degrades at a much slower rate. Moreover, β-tricalcium-phosphate (β-TCP) as a bone scaffold is both porous and degrades faster hence existing studies have used it to generate a dense extracellular matrix. Discussion: The studies examined in this paper highlight contributions made to scaffolds and microfluidics using bone-on-a-chip models. Notably, scaffolds must be osteoconductive to allow bone cells to adhere, proliferate and form an extracellular matrix on its surface and pore. While PDMS is both osteoconductive and biocompatible, its rigidity poses a concern. Both β-TCP and HA have capabilities for cell-mediated resorption and are more favourable substrates. Additionally, by incorporating microfluidics with bone-on-a-chip models, cells experience greater fluid shear stress similar to that of loading within the bone. Conclusion: In sum, advancements to bone-on-a-chip platforms are ongoing and the many published studies discussed in this paper aim to optimize both the design and materials used to create long lasting impacts on the rapidly growing field of cell and tissue engineering.

Introduction The JAK2V617F+ mutation occurs in up to 95% of patients with polycythemia vera (PV) and increases the risk of thrombosis 6-fold. Recent studies demonstrate that JAK2V617F+ endothelial cells express pro-adhesive proteins, suggesting that the endothelium may contribute to increased thrombosis.1-3 The targeted JAK1/JAK2 inhibitor ruxolitinib is an approved second-line therapy for PV patients and is effective in alleviating constitutional symptoms, lowering hematocrit, and reducing cell number. However, there is limited data regarding efficacy of ruxolitinib in reducing thrombosis. Although recent work has demonstrated ruxolitinib reduces neutrophil extracellular trap formation,4 the vascular effects of ruxolitinib are unknown. Therefore, we hypothesize that ruxolitinib reduces endothelial cell pro-adhesive activation leading to decreased rolling and adhesion of JAK2V617F+ samples. Methods To mimic JAK2V617F activation, primary human umbilical vein endothelial cells (HUVEC, passage 1-5) were treated with TNF-α (10 ng/mL) +/- ruxolitinib (400 nM-4 µM, Selleckchem) and characterized 4h later. For confocal microscopy, cells were fixed with paraformaldehyde, permeabilized and stained for either VWF, VCAM-1, or P-selectin along with 2-(4-amidinophenyl)-1H-indole-carboxamide (DAPI, Thermo Fisher). Images were captured on Olympus FluoView FV1000 IX2 Inverted Confocal microscope. Secretion of VWF, VCAM-1 and P-selectin into conditioned media was assessed with ELISA (Molecular Innovations; BioLegend). Citrated normal and JAK2V617F+whole blood was obtained per IRB and labeled with calcein AM (ThermoFisher). To quantify leukocyte and platelet velocity and adhesion, an endothelialized poly-di-methyl-siloxane (PDMS) microchannel was prepared and treated with TNF-α (10 ng/mL) +/- ruxolitinib (400 nM-4 µM). Samples were perfused through the microfluidic at a shear stress of 0.35 dynes/cm2, and 10 s images were captured using a fluorescence microscope (Olympus). Cell velocity and adhesion were quantified using FIJI (NIH). Results Compared to TNF-α treated HUVEC alone, the combination of ruxolitinib + TNF-α reduced expression of VWF, VCAM-1 and P-selectin using both immunofluorescence and ELISA. In endothelialized microfluidic devices treated with TNF-α alone, both normal (n=3) and JAK2V617F+ (n=9) leukocyte and platelet velocity was significantly decreased and cell adhesion increased. This result was independent of hematocrit and platelet levels. In normal controls (n=2), TNF-α+ruxolitinib lead to a trend toward normal leukocyte and platelet velocity with decreased cell adhesion. Lastly, in a small subset of JAK2V617F+ patients (n=4), addition of ruxolitinib increased cell velocity. Conclusions In conclusion, in TNF-α-activated endothelial cells, treatment with ruxolitinib decreases pro-adhesive VWF, VCAM-1, and P-selectin expression. Using normal controls and JAK2V617F+ MPN blood samples, our TNF-α-activated endothelialized microfluidics model demonstrates significant reduction in leukocyte and platelet velocity and increased cell adhesion. In normal and JAK2V617F+ MPN whole blood, treatment of TNF-α-stimulated endothelium with ruxolitinib improves cell velocity. Further evaluation using JAK2V617F+ endothelial cells is planned. Collectively, these results suggest that ruxolitinib may reduce JAK2V617F+ thrombotic risk through reduction of pro-adhesive endothelial activation. Disclosures Vercellotti: CSL Behring: Research Funding.

ABSTRACTPoly(m-carboranyl-siloxane) elastomers containing a mixture of di-methyl- and methyl(phenyl)-silyl units were synthesised using the Ferric Chloride catalysed condensation reaction between di-chloro-di-organosilane and 1, 7-bis(di-methyl(methoxy)silyl)-m-carborane. These prepared polymers were aged either by heating in air at elevated temperature or by λ-irradiation from a 60Co source. Multinuclear (1H, 13C and 11B) solid and solution state nuclear magnetic resonance was used to evaluate degradation. λ-irradiation doses to 1 MGy were found to induce only a small reduction in elastomer properties as evidenced by a reduction in segmental chain dynamics. Ageing at temperatures below 350°C similarly displayed a small reduction in segmental chain dynamics together and a concomitant weight loss as measured by differential scanning calorimetry. Above 350°C degradation of the elastomer was dramatic with a decreased segmental chain dynamics and oxidation of the carborane cage, vide infra.

Flexible Electronics is a multi-disciplinary domain that creates intersections among elec- tronics, materials-science, mechanics, packaging, sensor-design, etc., to build exible / stretchable / conformal electronic circuits and systems. The spectrum of this field is very broad, and hence the approaches, materials/substrates di er significantly based on applications and requirements. In the recent years, development of electronic circuits and systems on wearable elastomeric substrates has gained a lot of research attentions due to its possible applications in wearable bio-medical devices for clinical diagnostics, electronic-skin for prosthetic implants, artificial-skin for robotics, etc. Traditionally, prob- lems in exible electronics have been handled using two distinct approaches. The former approach involves fabrication of non-crystalline semiconductor based thin film transis- tors (TFTs) and integrated circuits on mechanically exible substrates. This approach is well-suited for applications like large-area displays, image-sensor arrays, etc. How- ever, this approach su ers from several issues like poor mobility, threshold voltage shifts, degradation on exposure to ambience, etc. Hence, this approach is not well-suited for applications requiring high-performance exible electronics with wireless capabilities. The latter approach to exible electronics involves packaging of conventional crystalline semi- conductor based integrated-circuit components on elastomeric substrates. This approach involves heterogeneous integration of rigid circuit components on conformal elastomers using stretchable interconnects, and hence involves addressing issues related to packag- ing and reliability. The usage of conventional electronics based circuit elements helps to build high-speed, wireless systems on elastomers, and hence this approach is well-suited for wearable electronics applications like clinical diagnostic devices. Motivated by such applications, the thesis concentrates on this latter approach of solving packaging problems on elastomers. The thesis begins with an exhaustive literature survey with regards to this packaging approach and finds some gaps/shortcomings which lead to several possible research questions such as: 1. How to develop fabrication processes/techniques for conformal electronics, which are in-line with conventional printed circuit board manufacturing processes, i.e. without use of specialized clean-room infrastructure, thin-film deposition facilities? 2. How to retain metals like copper for interconnects-layer in exible/conformal elec- tronic circuits, so as to achieve an excellent high-frequency operation in these cir- cuits? 3. How to design specialized meandered geometries for interconnect buses that satisfy all user constraints relating to: mechanical stress, electrical impedance, band-width, layout-area, etc.? These questions, along with the thrust to explore novel end-user applications, form the basic motivations for this thesis-work. The objective of this thesis is to develop a generic platform to package electronic circuits and sensors on conformal elastomeric substrates. The thesis focusses on developing and understanding packaging techniques and design rules needed for this generic platform. With regards to packaging of circuits on elastomers, the thesis discusses novel archi- tectures and fabrication techniques for developing stretchable copper interconnects and contacts to die-pads on PDMS (Poly Di-Methyl Siloxane) elastomer. The packaging tech- niques are characterized through relevant experiments, where circuit demonstrations are shown on elastomers for proof-of-concept. With regards to design rules for exible/conformal electronic circuits, an optimization platform is developed to help choose the best design for stretchable interconnect-buses used in these circuits. To achieve this, a generic meandered bus topology is proposed for the interconnect design. The impact of the proposed meandered-geometry on parametric functions such as mechanical stress, sti ness coe cient, electrical impedance, layout-area, packaging density, etc. are thoroughly investigated through analysis, simulations and experiments. The trade-o s relating to mechanical, electrical and layout-area functions are studied. Intuitive design rules are evolved based on these analysis and trade-o s. An optimization problem is formulated to help choose the best geometry for the meandered- buses, that satisfies all the given user-constraints such as: strain, impedance, layout-area, bus-width. The final part of the thesis discusses the development of percolation-based sensors on elastomeric substrates that can sense both strain and temperature. This sensor de- velopment is targeted towards very specific aerospace applications, where strain range of 0-10,000 micro.strain is of much interest for measurement along surfaces of launch vehicles and space-crafts. To summarize, the primary objectives of the thesis involve developing this generic plat- form for conformal electronic circuits/systems by engineering the building blocks, namely: i. stretchable interconnects, ii. contacts to die-pads, iii. sensors on elastomeric substrates. The thesis does not concentrate on specific system-building targeting a particular appli- cation. Most of the focus is given to understand and engineer these constituent building blocks for conformal electronics. This platform can be potentially applied for various end-user applications like: wearable bio-medical devices, smart-textiles, artifical skin for soft-robotics, electronic skin for prosthetic implants, energy harvesting on elastomers, etc.

The polysiloxane of greatest commercial importance and scientific interest is poly(dimethylsiloxane) (PDMS), [Si(CH3)2 –O –]x, a member of the symmetrical dialkyl polysiloxanes, with repeat unit [SiR2 –O –]x. This polymer is discussed extensively in the following chapters, particularly in chapter 5. Other members of this series are poly(diethylsiloxane) [Si(C2H5) –O–]x, and poly(di-n-propylsiloxane) [SiC3H7)2–O–]x. An example of an aryl member of the symmetrically substituted series is poly(diphenylsiloxane), with repeat unit [Si(C6H5)2–O–]x. This polymer is unusual because of its very high melting point and the mesophase it exhibits. The closely related polymer, poly(phenyl/tolylsiloxane), has also been prepared and studied. The unsymmetrically substituted polysiloxanes have the repeat unit [SiRR’O–]x, and are exemplified by poly(methylphenylsiloxane) [Si(CH3) (C6H5) –O–]xand poly(methylhydrosiloxane) [Si(CH3)(H) –O–]x. In some cases, one of the side chains has been unusually long, for example C6H13, C16H33, and C18H37, including a branched side chain—CH(CH3– (CH2)m–CH3. Another example has methoxy-substituted aromatic fragments as one of the two side chains in the repeat unit. Such chains have stereochemical variability in analogy with the vinyl polymers such as polypropylene [CH(CH3) –CH2–]xand vinylidene polymers such as poly(methyl methacrylate) [C(CH3)(C = OOCH3) –CH2–]xOne can also introduce optically active groups as side chains, the simplest example being the secondary butyl group—CH(CH3)(C2H5). Another example involves redox-active dendritic wedges containing ferrocenyl and carbonylchromium moieties. Other substituents have included phenylethenyl groups, cyclic siloxane groups, and Cr-bound carbazole chromophores. In a reversal of roles, some polymers were prepared to have PDMS side chains on a poly(phenylacetylene) main chain. Siloxane-terminated solubilizing side chains are used to improve the properties of thin-film transistors. Silalkylene polymers have methylene groups replacing the oxygen atoms in the backbone. Poly(dimethylsilmethylene) is an example, [Si(CH3)2–CH2]x. A variation on this theme is to include aryl groups, for example, in poly(dimethyldiphenylsilylenemethylene) [Si(CH3)2CH2Si(C6H5)2]x. Other aryl substituents, specifically tolyl groups, have also been included as side chains. It is also possible to insert a silphenylene group [Si(CH3)2–C6H4–] into the backbone of the polysiloxane repeat unit to give [Si(CH3)2–C6H4– Si(CH3)2O–], in which the phenylene can be para or ortho or meta. A specific example is poly(tetramethyl-p-silphenylene-siloxane).

On-chip isoelectric focusing (IEF) has been performed in both straight and dog-leg microchannels. Three-dimensional microfluidic chips were fabricated on poly di-methyl-siloxane (PDMS) using soft lithography and multilayer bonding techniques. Plasma oxidized PDMS channel surfaces were dynamically coated with methyl cellulose to discourage electroosmotic flow during separation and purification processes. In a straight microchannel, IEF was completed within 5 minutes at an applied electric field strength of 50 V/cm using broad range ampholytes. The focused bands were generally well-formed with sharp edges and were less than 100 microns across yielding a putative peak capacity in excess of 100 peaks in a 2-cm long channel. However, the conventional IEF protocol shifts the focused bands toward the cathodic well. This cathodic drift can be effectively minimized by placing highly viscous polymer solutions in the electrode reservoirs. In dog-leg microchannels, initially well formed focused band dispersed at the Tee-channel junction, but refocused at the dog-leg channels with relatively lower resolution.

This experimental study reports a method to increase the resolving power of isoelectric focusing (IEF) on a polymeric microfluidic chip. Microfluidic chip is formed on poly-di-methyl siloxane (PDMS) using soft lithography and multilayer bonding technique. In this novel bioseparation technique, IEF is staged by first focusing protein species in a straight channel using broad-range ampholytes and then refocusing segments of that first channel into secondary channels that branch out from the first one. Experiments demonstrated that three fluorescent protein species within a segment of pH gradient in the first stage were refocused in the second stage with much higher resolution in a shallower pH gradient. A serially performed two-stage IEF was completed in less than 25 minutes under particularly small electric field strength up to 100 V/cm.

A conductivity based on-chip flow sensor is introduced to measure the velocity of liquid-gas interface in microchannels for lab-on-a-chip applications. This sensor is used to evaluate the performance of planar electrokinetic micropumps formed on hybrid poly-di-methyl-siloxane (PDMS)-glass platform. In this study, the micropump thickness is varied between 3.5 and 10 microns, and the externally applied electric field of electrokinetic pump is ranged from 100 V/mm to 200 V/mm. For all channel dimensions and for all electric fields, fairly repeatable flow results are obtained from the speed of liquid-gas interface. Flow results obtained from this interface tracking method are compared to those of other existing flow measuring technique. The maximum error of this micro flow sensor is less than 5%, even in ultra low flow velocity.

A microfluidic flow sensor has been developed to precisely measure the flow rate in a micro/nanofluidic channel for lab-on-a-chip applications. Mixed electroosmotic and pressure driven microflows are investigated using this sensor. Our microflow sensor consists of two components: fluidic circuit and electronic circuit. The fluidic circuit is embedded into the microfluidic chip, which is formed during the microfabrication sequences. On the other hand, the electronic circuit is a microelectronic chip that works as a logical switch. We have tested the microflow sensor in a hybrid poly di-methyl-siloxane (PDMS)-glass microchip using de-ionized (DI) water. Softlithography techniques are used to form the basic microflow structure on a PDMS layer, and all sensing electrodes are deposited on a glass plate using sputtering technique. In this investigation, the microchannel thickness is varied between 3.5 and 10 microns, and the externally applied electric field is ranged between 100V/mm and 200V/mm. The thickness of the gold electrodes is kept below 100nm, and hence the flow disturbance due to the electrodes is very minimal. Fairly repeatable flow results are obtained for all the channel dimensions and electric fields. Moreover, for a particular electric field strength, there is an appreciable change in the flow velocity with the change of the channel thickness.

An integrated micro-fluidic chip has been developed using Poly-di-methyl siloxane (PDMS) to separate proteins by isoelectric focusing (IEF). Soft lithography techniques, which offer rapid prototyping, easy multilayer fabrication, mass production capability and biocompatibility, were utilized to fabricate various parts of the micro-fluidic chip. Separately molded PDMS layers were bonded together to form three-dimensional microfluidic chips. The microfluidic chips were prepared for IEF by conditioning the channel with 1 M NaOH and then loading it with a solution of fluorescent proteins made using 0.4% MC, 4% broad-range ampholyte and 0.018 mg/ml protein in 18 MOhm water. Relatively large reservoirs on the acidic and basic ends of the channel were filled with anolyte (50 mM phosphoric acid) and catholyte (50 mM sodium hydroxide), respectively, and then current was applied along the axis of the channel until one or more bands of protein focused, usually in just a few minutes even at relatively low voltages. The focused bands were generally well-formed with sharp edges and were less than 100 microns across yielding a putative peak capacity in excess of 100 peaks in a 2-cm long channel.

The thermal performance of nanofluids in microchannel of rectangular cross-section was experimentally investigated in this study. In the previous studies, a threshold nanoparticle concentration exists where the critical concentration separates the heat transfer performance of the nanofluid during a flow through microchannels. Thus, the emphasis of our study is to find the optimum concentration value of nanoparticles for enhancing the forced convective heat transfer coefficients. In this study, thin-film thermocouple array (TFTA) of K-Type (Chromel/ Alumel) was employed to measure the temperature profile on the heated surface in the microchannel (while the top and wall was sufficiently insulated). The TFTA deposited on a silicon wafer is bonded with a polymer substrate containing the molded microchannel. The microchannel was made using the Poly Di-Methyl Siloxane (PDMS). The mold for the microchannel in order to cure the PDMS onto it was fabricated using soft-lithography technique on an atomically stable silicon substrate. To assess the thermal performance of nanofluids in micro-channels, the temperature profiles in the heated bottom wall of the micro-channel was monitored using the TFTA which was then used to estimate the wall heat flux values. The concentration and size of the silica nanoparticles in the aqueous nanofluids are parametrically varied in this study (e.g. at weight concentrations of 0.5%, 0.1% and 0.2%). These parametric experiments were performed by varying the wall temperatures (e.g. 30, 50 and 70 °C) and flow rates (e.g. 5, 7 and 9 μl/min).

Abstract A normally-open thermally-actuated microvalve was designed (using microfabrication/soft-lithography techniques involving 3D Printed molds), assembled and tested. The motivation of the research work is to develop an array of microvalves for precise delivery of water to individual plants in a field (with the goal of developing smart irrigation systems for high value cash-crops in the agricultural sector). It is currently impossible to control application of irrigation-water at the level of a single plant. If such a capability were practically available on farms, the result would be a step change in precision agriculture, such that the output of every plant in a farm field could be optimized (i.e., food-water-energy nexus in sustainability applications). The aim of this study is to develop and test a microfluidic system (consisting of a microvalve array) that could be controlled, capillary by capillary, to deliver the needed amount of water to individual plants in a large field. Two types of test fluids were leveraged for thermo-hydraulic actuation of the microvalves developed in this study: (a) Design-I: using air, and (b) Design-II: using Phase Change Material (PCM). The PCM used in this study is PureTemp29. The proposed approach enabled a simple and cheap design for microvalves that can be manufactured easily and are robust to weather conditions (e.g., when exposed to the elements in orchards and open fields). Other advantages include: safe and reliable operation; low power consumption; can tolerate anomalous pressure loads/fluctuations; simple actuation; affords easy control schemes; is amenable for remote control; provides long-term reliability (life-cycle duration estimated to be 3∼5 years); can be mass produced and is low maintenance (possibly requiring no maintenance over the life time of operation). The microvalve consists of two layers: a flow layer and a control layer. The control layer is heated from below and contains a microfluidic chamber with a flexible polymeric thin-membrane (200 microns in thickness) on top. The device is microfabricated from Poly-Di-Methyl-Siloxane (PDMS) using soft lithography techniques (using a 3D Printed mold). The control chamber contains either air (thermo-pneumatic actuation) or PCM (thermo-hydraulic actuation involving repeated melting/freezing of PCM). The flow layer contains the flow channel (inlet and outlet ports, horizontal section and valve seat). The experimental results from testing the efficacy of the two types of micro-valves show a 60% reduction (for thermo-pneumatic actuation using air) and 40% reduction (for thermo-hydraulic actuation using PCM) in water flow rates for similar actuation conditions (i.e., heater temperature values). PCM design is expected to consume less power (lower OPEX) for long-term actuation but may have slower actuation speed and have higher manufacturing costs (CAPEX). Air actuation design is expected to consume more power (higher OPEX) for longer-term operation but may have faster actuation speeds and lower manufacturing costs (CAPEX). Computational Fluid Dynamics (CFD) simulations were performed to investigate the effect of flowing water (in the microfluidic channel) on the average absolute pressure and temperature of air in the actuation chamber. The CFD simulations were performed using a commercial tool (Ansys™ 2019R1®). The results from the CFD simulations are presented in this study.