藉由高分子氫鍵作用力的轉換來控制高分子薄膜表面特性之研究

Abstract

摘要

本論文中以討論高分子氫鍵作用力及多面體聚矽氧烷奈米粒子對於高分子薄膜表面特性的為主體，分為五大主題:

1. 利用低溫交聯的Polybenzoxazine薄膜去修飾高分子薄膜表面 在我們以前的研究發現Polybenzoxazine薄膜為一低表面能材料，可以用來修飾無機固體表面如金屬、玻璃或矽晶圓等等。但是對於高分子材料其熱交聯製程溫度太高因此無法去修飾高分子表面。在本章中我們發現AIBN此自由基起始劑在120℃製程下由於起始劑化學鍵斷鍵所產生的熱能可以產生一些寡聚物，而這些寡聚物會對熱交聯反應產生催化效果。因此我們利用此低溫製程成功的修飾高分子基材，史的這些高分子表面也具有低表面能特性。

2. 控制Polybenzoxazine薄膜表面能之研究 Polybenzoxazine 薄膜由於具有極強的高分子內氫鍵而擁有極低的表面能，我們利用了熱與紫外光這兩種方式來控制Polybenzoxazine薄膜中分子內與分子間作用力的比例。 藉由這兩種方式我們可以輕易的控制Polybenzoxazine薄膜的表面能。此外，我們更利用紫外光照時間與區域的不同在Polybenzoxazine薄膜 上製造親疏水性圖案的陣列與梯度。並且成功的製造出鍗化鎘量子點的規則陣列。 3. 製造擁有超疏水及超親水特性的Polybenzoxazine 有機無機混成表面 我們利用混掺二氧化矽奈米粒子提高表面粗糙度以製造具有蓮花效應的超疏水表面。再利用紫外光照讓某些特定區域形成超親水的表面，藉此我們可以得到同時具有超疏水及超親水兩種極端特性的表面。此外，在紫外光照後我們發現表面對於水滴產生極強的吸附力。我們將表面光照後產生的此特性應用在能轉移微小水滴的機械手臂上。此外我們更利用表面分析化學分析影像能譜儀對光照後的表面化學組成改變作更深入的探討。 4. 分子量及高分子氫鍵作用力對於低表面能材料Poly(4-vinyl phenol)表面特性影響之探討 在我們先前研究發現Poly(4-vinyl phenol)為一低表面能材料。在此章中我們更深入的探討分子量、多面體聚矽氧烷奈米粒子及高分子氫鍵作用力對於Poly(4-vinyl phenol)高分子薄膜表面特性的影響。為了探討高分子氫鍵的影響我們合成了不同比例的Poly(4-vinyl phenol)/Poly(methyl methacrylate) 團塊塊體共聚合物及不規則共聚合物。在其中我們發現 Poly(4-vinyl phenol)/Poly(methyl methacrylate) 團塊塊體共聚合物及不規則共聚合物系統不同於混掺系統呈現非常低的表面能，這是因為團塊塊體共聚合物及不規則共聚合物系統在熱處理在快速冷卻的過程中降低了分子間的作用力。而混掺系統雖然也降低了Poly(4-vinyl phenol)之間的分子作用力卻也增加了Poly(4-vinyl phenol)與Poly(methyl methacrylate)分子鏈之間的作用力。所以混掺系統的表面能會隨著Poly(methyl methacrylate)的含量增加而增加。

5. 多面體聚矽氧烷奈米粒子對於poly(4-vinyl phenol)表面特性與溶液相行為影響之探討 多面體聚矽氧烷奈米粒子本身為一具有低表面能的奈米粒子，所以不管當我們是混摻或是接枝上去poly(4-vinyl phenol)此種高分子上面，我們均發現隨著多面體聚矽氧烷奈米粒子的量越多，高分子薄膜的表面能降的越低。此外我們也發現在末端帶有多面體聚矽氧烷奈米粒子的Poly(4-vinyl phenol) 團塊塊體共聚合物在溶液中呈現非常獨特的自組裝行為。

Abstract

In this study, we focus on five major subjects which based on the effect of hydrogen bonding and POSS nanoparticle on surface free energy:

1. Modification of Polymer Substrates with Low Surface Free Energy Material by Low-Temperature Curing Polybenzoxazine The B-ala/AIBN PBZ system has a higher extent of the ring-opening of oxazine because phenol-containing oligomers are formed at the early stage of the curing process. As a result, the B-ala/AIBN PBZ system possesses a relatively stronger intramolecular hydrogen bonding and lower surface energy than the pure B-ala system at low temperature curing. In this context, Poly(4-vinyl pyridine), Poly(4-vinyl phenol) thin film and polycarbonate substrates which lack liquid resistance possess low surface free energy after modification with B-ala/AIBN = 5/1 PBZ. 2. Tuning the Surface Free Energy of Polybenzoxazine Thin Films A novel approach to manipulate the surface free energy and wettability on polybenzoxazine thin films can be achieved simply by varying time of thermal treatment or UV exposure. Fraction of the intramolecular hydrogen bonding of the as cured sample will convert into intermolecular hydrogen bonding upon thermal treatment or UV exposure and thus results in increase of hydrophilicity and wettability. This UV approach provides a simple method to generate wettability patterns or wettability gradients on the surface of polybenzoxazine film. In addition, we have applied this technique to the preparation of a large-area periodic array of CdTe colloidal nanocrystals on polybenzoxazine thin films.

3. Fabrication of patterned superhydrophobic Polybenzoxazine-hybrid surfaces The hydrophilicity of B-ala PBZ film and superhydrophobic polybenzoxazine-hybrid surface can be controlled through UV exposure to change ratio of intra- to intermolecular hydrogen bonds. Fraction of the intramolecular hydrogen bonding of the as cured sample will convert into intermolecular hydrogen bonding upon UV exposure and thus results in increase of hydrophilicity. This simple method allows for manipulating the hydrophilicity at selected regions on superhydrophobic polybenzoxazine-hybrid surface to create patterned surface with superhydrophobic and superhydrophilic regions. Besides, we have found that the superhydrophobic polybenzoxazine-silica hybrid surface exhibits good adhesion of water droplets after UV exposure which can be served as a “mechanical hand” to transfer water droplets from a superhydrophobic surface to a hydrophilic one. 4. Effect of molecule weight and hydrogen bonding on low-Surface-Energy material of poly(vinylphenol) We discovered that a series of poly(vinylphenol-co-methylmethacrylate) (PVPh-co-PMMA) block and random copolymers possess extremely low surface energy after a simple thermal treatment procedure, even lower than that of poly(tetrafluoroethylene) (22.0 mJ/m2) calculated on the basis of the two-liquid geometric method. The decrease of the intermolecular hydrogen-bonding fraction between hydroxyl groups of PVPh in PVPh/PMMA systems through a simple thermal treatment procedure tends to decrease the surface energy and the sequence distribution of the vinylphenol group in PVPh-co-PMMA copolymers plays an important role in dictating the final surface energy after thermal treatment.

5. Effect of POSS nanoparticle on Surface Free Energy and Phase Behavior POSS-PAS copolymer was systhesed by atomic transfer radical polymerization with POSS-Cl initiator as a macroinitiator which was obtained by using corner-capping reaction. POSS-PVPh copolymer was obtained from the hydrolysis of POSS-PAS copolymer. We found that the POSS nanoparticle would decrease the polymer surface free energy in both POSS/PVPh and POSS-PVPh systems. With incrasing the content of POSS nanoparticle on polymer thin film surface the surface free enegy of polymer thin film would decrease dramatically. We also found that the POSS-PVPh copolymers possessed unique phase behavior in solution state and the superhydrophobic surface was prepared from POSS-PVPh in a THF/toluene mix solution.