藉由lotus effect 之原理來探討超疏水性表面的製備
超疏水表面(superhydrophobic surface)因其自我清潔效果在近年來引起廣泛的研究及探討，目前世界各大公司皆積極投入自潔性產品(超疏水表面)的研發，但是截至目前為止除了塗料及織物有產品外，其他尚在研發階段。降低表面能及增加表面粗糙度為製作超疏水性表面的兩種方法。本實驗我們針對使用不同方法去仿照自然界植物「蓮花效應」，將二氧化矽粒子適當的分佈在基材表面，以增加粗糙度，製造出超疏水性表面。我們發現鍛燒會使其二氧化矽粒子黏聚在一起，對接觸角的增加無幫助。而在溶膠凝膠的配置過程中直接加入OTS(Octadecyltrichlorosilane)，並利用光散射儀比較二氧化矽奈米顆粒的平均粒徑及粒徑分佈隨時間變化的情形，一段時間後發現會有明顯大顆粒沉澱，塗佈在玻璃基材表面後容易脫落，不適合往後實驗或其他用途。而以氨水催化的溶膠凝膠以不同流速滴入TEOS (Tetraethylorthosilicate，四乙氧基矽)對接觸角的影響也不大。最後我們利用砂紙在基材表面上刷磨，可以使二氧化矽粒子分佈均勻，明顯增加接觸角。塗佈速率的改變搭配疏水性矽烷單分子膜的改質，我們已可以製造出159°的超疏水性表面。Superhydrophobic surfaces are generally made by lowering the surface energy and increasing the surface roughness. In this experiment, we use different methods of spreading silicon dioxide nanoparticles properly on the surface in order to increase the surface roughness and also make superhydrophobic surfaces. In the beginning, we find that the calcinations can cause its silicon dioxide nanoparticles to stick together instead of increasing the contact angles. Then, add OTS (Octadecyltrichlorosilane) directly to manufacture process of sol-gel, and observe the situations of the average length and the spread of silicon dioxide nanoparticles with the time goes by. After a period of time, we will discover that many obvious big particles deposit and spin-coating on the glass surfaces flop easily. Hence, this phenomenon is n’t proper for the following experiments or other uses. However, the contact angles have nothing to do with dropping the sol-gel catalyzed ammonia to TEOS(Tetraethylorthosilicate) by different flowing rates. Finally, it is crucial for us to use the sandpapers to brush on the surfaces because it may cause the silicon dioxide nanoparticles to spread well and obviously increase the contact angles. Combining the silicon dioxide surfaces with the change of spin-coating rate and the cover with hydrophobic SAM, we have made the superhydrophobic surfaces of 159°.
大自然的飛行家--蝴蝶飛行之初部探討
本研究主要針對蝴蝶之飛行進行探討，研究中主要探討蝴蝶翅膀形狀、身體重量、翅膀面積、展弦比、拍翅頻率及環境溫度對飛行速率之影響，並利用自製之風洞裝置，觀察蝴蝶之翼翅運動，分析通過蝴蝶模型之氣流方向及相關氣動力。研究結果顯示：紋白蝶展翅約4.5~5 cm，平均展弦比(AR)為1.71 ± 0.12，身體重量約為0.06± 0.02 g，翅膀面積約0.0012 ± 0.0003 m2，當紋白蝶身體重量愈重，則翅膀面積愈大(R2=0.9586)。另外，紋白蝶身體重量愈重、展弦比愈小，則飛行速率亦愈快(R2=0.5559、R2=0.4726)。23℃時，紋白蝶飛行速率為1.01±0.24 m/s，當環境溫度愈高(5、16、23℃)，則飛行速率亦愈快(y=0.07x＋0.7733，R2=0.6967)。風洞實驗發現：蝴蝶會逆風而飛，當風洞的風愈強，蝴蝶翅膀拍動角度愈大，且快而持久，仰角也變大(45 度)；蝴蝶翼尖軌跡呈八字形，翼翅運動包含線性平移及旋轉；蝴蝶拍翅時，可在翅上方及前方產生低壓帶，在後方產生高壓帶，以利蝴蝶向前方飛行。另外，翅緣彎曲角度(上反角)愈大，蝴蝶模型之上升高度亦愈高，當上反角60°時，蝴蝶模型之上升高度最高(2.2±0.1cm)。This research approaches the flying ability of butterflies. Our research mainly discusses the weight, aspect –ratio of butterflies, frequency of flapping, and the shape, surface area of butterflies’ wings, and the connection between temperature and flying velocity. More over, we use the wind tunnel which was made by us to observe the movement of butterflies’ wings and analyzed the direction of airflow and aero-elastic which pass through the wind tunnel. Our research shows that Pieris canidia’s length of wings is about 4.5 to 5 cm. The average of aspect –ratio (AR) is 1.71±0.12 . Its weight is about 0.06±0.02 . And its surface area is about 0.0012±0.0003 m 2 . The heavier Pieris canidia is, the bigger its surface area will be (R2 =0.9586). In addition, the heavier it is, the smaller its aspect –ratio will be (R2 =0.5559, R2 =0.4726), and the swifter its flying velocity will be. When it is 23°C, the flying velocity of Pieris canidia is 1.01±0.24m/s. The hotter temperature is (5,16,23°C), the swifter it flies (y=0.07x+0.7733,R=0.6967). Accroding to the detect of the wind tunnel’s experiment , the butterflies will fly on luff. When the stronger the wind of the wind tunnel is, the larger the angles of wing’s flap are. And they are fast and lasting, the elevation also becomes larger (45°). The butterflies’ trochoids of wings mimic the word “eight”, and the movement of wingspan includes parallel movement of linearity and wheel. When butterflies flap, it will amount depression upon and in front of the wings, amounting the high pressure on the back so that butterflies can fly antrorsely. Furthermore, the larger the curvy angle of marginal wings (Dihedral) is, the higher the ascending height of model butterfly will be. When dihedral is 60°, the ascending height of model butterfly is the highest(2.2±0.1 ㎝).
A Novel Contrast-Enhanced Brain Mimicking Hydrogel for Testing Implantable Brain Electrodes
Paralysis is a debilitating disorder that does not currently have safe and effective treatments. Implantable brain electrodes can be used to read brain waves and convert them into a corresponding motor function to restore movement in paralyzed patients. Tissue deformation induced around the implant site is believed to reduce their viability through the foreign body response. Developing electrodes that minimize deformation is challenging because the mechanical aspects of deformation are not fully understood and non-animal tissue models for testing electrodes are unavailable. Development of pre-clinical models for in vitro testing of the mechanical properties of electrodes can lead to a better understanding of this prevalent problem. The objective of this study was to construct a novel contrast-enhanced, brain mimicking hydrogel using photopolymerizable polyethylene glycol (PEG) polymer that contains alginate microspheres with enclosed gadolinium (Gd) contrast agent. 1.5% alginate microspheres were constructed with enclosed Gd-DTPA-BSA contrast agent and successively added into 10% PEG. Then, this mixture was photopolymerized using a 5 mW/cm2UV lamp to result in a successful brain mimicking hydrogel. Rheological testing showed that its elastic modulus was approximately 1.5 kPa, which is similar to that of a normal human brain. The model is valuable because the presence of the contrast agent in the hydrogel resulted in distinct bright spots on the MRI. This can facilitate the visualization of tissue deformation caused by electrode insertion via comparison of pre-insertion and post-insertion images. This brain-mimicking model has the potential to improve understanding of neural deformation from electrode implants in order to assist patients suffering from paralysis.
仿生智慧型熱控制系統
通常使用隔熱材料可以降低熱量傳遞，而使用風扇、散熱片、熱導管等用來單向散熱。但如何在一個系統上同時滿足隔熱和雙向傳熱的需求呢？因此我研究設計了仿生智慧型熱控制系統，能隨環境改變而快速轉變成隔熱或轉變成雙向傳熱並控制熱傳遞的方向及大小，這可以應用在房屋、汽車、恆溫系統等。我先自製了自動傳熱量測系統，測試並找出好的隔熱和傳熱材料及構造。為了能快速控制熱的方向及大小，我又發展了第一代替換式、第二代熱柵式和第三代熱管式熱控制系統；經過多次實驗，利用低沸點有機溶劑和控制系統，我成功地完成仿生智慧型熱控制系統，讓熱隔絕或快速流進流出，比傳統的方法改進很多，也達到節約能源的目的。Insulation materials are usually used to reduce heat transfer rate, while fans, radiators and heat pipes are applied to increase heat transfer rate and bring heat away. But is it possible to have both functions of insulation and heat transfer together in a single system? This research is to design and develop an intelligent heat control system, with both function of insulation and function of transferring heat together. Besides, this system can control the direction and amount of heat transferred. Such a system can be applied in house walls, cars, thermostatic system, etc. I developed an automatic heat measurement system which was used to test the properties of heat transfer for different materials and structures. Three generations of intelligent bi-directional automatic heat control system were then developed to get fast heat transfer and function of heat control. They were phase 1 replacing-type system, phase 2 heat-grating system, and phase 3 heat-pipe system. After tens of experiments, I successfully control the amount and rate of heat transfer via low-boiling-point organic solutions and controller. The designed system is bi-directional, and is more innovative and efficient than conventional uni-directional heat control methods. Besides, this system also has huge contribution in reducing energy consumption.