本研究合成不同聚合度的聚乳酸( PLLA ,聚合度= 60~ 468 )與聚丙二醇( PPG , Mn= 4000 g/mol )三團聯共聚物(PLLA-PPG-PLLA)。使用偏光顯微鏡方法探討不同長度的PLLA鏈段，對球晶成長動力學參數的影響，並探討參數如何受軟段與硬段之間分子間作用力影響。以Hoffman-Weeks方法估計平衡熔點與增厚係數，再估計平衡晶片厚度，並討論平衡晶片厚度與硬段長度之標度關係。另外，利用不同PLLA聚合度PLLA-PEG-PLLA三團聯共聚物包覆藥物Vitamin K3的釋放實驗數據，以官能基貢獻法與Leibler臨界微胞濃度理論，估算硬核與水交互作用參數，探討硬核與水之間交互作用力對藥物釋放的影響。最後，以Higuchi溶出模型、Fickian球釋放模型與Fickian具無因次膜阻力模型，分析釋放實驗數據。
以log G0對硬段長度的倒數作圖，發現相同硬段的共聚物斜率，隨軟段與硬段之間交互作用力參數χAB值變小而變小。在硬段長度為無限長的共聚物G0，與可結晶鏈段的均聚物的G0接近，顯示硬段長度無限長的截距，軟段效果對G0的影響甚小。以摺曲表面之界面自由能σe對硬段長度的倒數作圖，發現硬段長度增加時，σe也會增加；而硬段長度無限長的截距，仍受到軟段效果的影響。
討論平衡晶片厚度與硬段長度的標度指數α值關係，發現相同硬段的共聚物，隨著軟段與硬段之間交互作用力參數χAB值變大，α值變小；非平衡晶片厚度與硬段長度的標度指數α'值對χAB值也有相同的趨勢，且標度指數α'值比標度指數 α值小。
在藥物釋放實驗中，以官能基貢獻法求得硬段與水之間交互作用參數χPLLA-water，會介於Leibler臨界微胞濃度理論計算求得不同硬段長度和水之χPLLA-water的最大與最小值之間。
藉由加入無因次膜阻力(π3)因素，修改Fickian球釋放模型。將Fickian具無因次膜阻力模型，以藥物釋放率對無因次時間作圖，發現隨著π3變小，藥物越難擴散至微胞外。
使用簡化的Higuchi藥物溶出模型(π2為無限大)與簡化的Fickian球藥物釋放模型(π3為無限大) ，計算出的擴散係數値分別為真實的高值和低值，對硬段長度的倒數作圖，發現擴散係數値隨著硬段長度增加而變小，真實的擴散係數値會落在 10-16 ~ 10-17 cm2/s的範圍之間。

Poly(L-lactide) -poly(propylene oxide)-poly(L-lactide) (PLLA-PPG-PLLA) triblock copolymers with PPG (The number average of molecular weight =4000 g/mol) and various PLLA length (degrees of polymerization from 60 to 468) were synthesized. The equilibrium melting point and spherulitic growth rate of copolymers were examined with polarizing microscopy . In conjunction with data, the Hoffman nucleation theory was used to obtain kinetic parameters such as nucleation constants (Kg), pre-exponential factor (G0), and fold surface energy (σe). We explore the influence of molecular interaction between the soft and hard segments on the kinetic parameters. The thickness of equilibrium lamellare was calculate, via equations by Hoffman-Weeks and Gibbs-Thomson-Tammann . In addition, we explore the interaction parameters between hard core and water in experiments of Vitamin K3 release from PLLA-PEG-PLLA triblock micelles. Finally, Higuchi model, Fick’s release model, and Fick’s model with the dimensionless resistance to analyze the drug release experimental data.
We plot logarithm of pre-exponential factor (log G0) versus the reciprocal of the hard segment length. It is found that slope of plot increase with Flory-Huggins interaction parameters between blocks, with a same hard block. Besides, when G0 at hard segment length equal to infinite, is almost the same as that of homopolymer with hard-segment . We plot fold surface energy versus the reciprocal of the hard segment length in different block copolymers, showing that, as long as length of hard segment increases, the fold surface energy increases.
The scaling exponent values (α) in the relations of the thickness of equilibrium lamellae versus hard segment length, show that Flory-Huggins interaction parameters between soft segment and hard segment become larger, as the scaling exponent values are smaller.
In the drug release experiment, group contribution method is used to calculate the Flory-Huggins interaction parameter between hard segments and water parameters, that will fall between the maximum and minimum values for Flory-Huggins interaction parameters by Leibler’s critical micelle concentration theory for a variety of block copolymers.
A dimensionless resistance factor (π3) is added to modify Fick’s release model in sphere. We plot drug release (1-F) versus the dimensionless group π1 at different values of π3. It is found that diffusion of the drug in micellar particles is reduced with decreasing dimensionless resistance factor.
Using simplified Higuchi model ( at drug loading approaching infinite), calculated diffusion coefficient values is greater than the true values. Using simplified Fick’s release model in sphere, calculated diffusion coefficient is smaller than true values. We plot drug diffusion coefficients versus reciprocal of the hard segment length. It is found that the true diffusion coefficients will fall between the range of 10-16 ~ 10-17 cm2/s.

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