Preparação e Avaliação da Atividade Catalítica de Polímeros de Condensação de Metilpiridinas e Tereftalaldeído em Reações de Nitroaldol e Cicloadição Heterodipolar [3+2]

Nesse estudo, foram preparadas bases poliméricas derivadas de 2,6-dimetilpiridinas e tereftaladeído utilizando a 2,4,6-trimetilpiridina como agente de reticulação. As resinas foram sintetizadas sob aquecimento convencional e purificadas por precipitação em metanol, apresentando rendimentos variando de 59 a 95%. Os copolímeros produzidos foram caracterizados por análise termogravimétrica (TGA), ressonância nuclear magnética de núcleo de hidrogênio (RMN-1H) e espectroscopia na região do infravermelho com técnica de ATR (FTIR - ATR), além de sua atividade básica. A capacidade catalítica do material produzido foi avaliada em reações nitroaldólicas, do tipo Henry, tanto em aquecimento convencional quanto com o uso de reator de micro-ondas. Não sendo observada atividade catalítica significativa para as resinas testadas, nestas reações. O material polimérico produzido também foi testado como suporte para cobre na catálise de reações de cicloadição heterodipolar do tipo [3+2] com benzilazida e propiolato de etila, para a formação de triazóis, processadas em reator de micro-ondas e sob aquecimento convencional. A reação mostrou-se regiosseletiva e processos de reciclo do catalisador se mostrou eficiente em reações consecutivas

Estudo de fatores prognósticos em pacientes submetidos ao transplante de medula óssea para tratamento de leucemia mielóide crônica.

O presente estudo compreende 96 transplantes de medula óssea (TMO) de doadores HLA-idênticos em pacientes portadores de Leucemia Mielóide Crônica, no período de Junho de 1986 a Junho de 1998. A autora selecionou diversas covariáveis para serem estudadas como fatores prognósticos de cinco desfechos principais: ocorrência de doença enxerto contra hospedeiro (DECH) aguda e crônica, incidência de recaída, sobrevida livre de doença (SLD) e sobrevida global (SG). As covariáveis estudadas foram: idade, sexo, escolaridade, tempo entre o diagnóstico e o transplante, fase da doença ao transplante, regime de condicionamente, profilaxia de DECH, compatibilidade de sexo entre doador e receptor, sexo do doador, tamanho do baço e do fígado, percentagem de blastos e número de plaquetas no sangue periférico na primeira consulta ao CEMO, ocorrência e grau de DECH aguda, ocorrência de DECH crônica e tempo para recuperação de plaquetas após o TMO. Não foi encontrada associação estatisticamente significativa num nível de 95% de confiança entre qualquer das covariáveis e a ocorrência de DECH crônica ou de recaída. A ocorrência de DECH aguda mostrou-se associada apenas com a fase da doença ao transplante. As covariáveis que se mostraram associadas com a sobrevida global e a sobrevida livre de doença foram: a percentagem de blastos no sangue periférico e tamanho do baço na primeira consulta ao CEMO, a fase da doença ao transplante, o tipo de profilaxia de DECH, a ocorrência e o grau de DECH aguda e o tempo para recuperação de plaquetas num nível acima de 20 x 103/mm3.

陆地棉抗虫基因工程研究

以陆地棉（Gossypium hirsutum L.）栽培品种新陆早4号、系550、冀资492、衡无89-30、邯93-2、冀资123等为材料，进行了组织培养及植株再生研究，建立了一套陆地棉体细胞植株再生速成体系。通过调整激素种类与比例以及改善培养条件，降低了畸形胚发生频率（从80%降为41%），并可将畸形苗转化为正常苗（转化率约为78%）;通过水培和嫁接，结合试管扦插、扩繁技术，解决了棉花生根及移栽难题，为农杆菌介导法转化棉花奠定了基础。 用绿色荧光蛋白基因（gfp）作为报告基因，构建了pBGb1m（含Bt和gfp二价基因）、pBGbf（含Bt-gfp融合基因）和pBGbfg（含Bt-gfp融合基因和gna基因）等三种植物表达载体。通过农杆菌介导法转化烟草，转基因再生植株经过荧光、虫试、PCR、Southern blot和Western blot等检测，表明三种植物表达载体能够在转基因植物中有效表达，同时，绿色荧光蛋白（GFP）的检测表现出了简便、经济、快速、可靠等优点，为大量棉花转基因苗的检测提供了一种有效方法。 采用花粉管通道法将携带细胞间隙定位信号肽的Bt基因的pBin438-S1m质粒导入棉花品种冀资492，经过田间卡那霉素筛选、虫试、PCR、PCR-Southern blot和Southern blot检测，证明Bt基因已整合至棉花基因组中，而且可能是以单拷贝形式插入。 同时，通过农杆菌介导法将三种植物表达载体（pBGb1m、pBGbf和pBGbfg）转化陆地棉栽培品种新陆早4号、冀资492、衡无89-30和邯93-2等材料，获得了大量转化再生棉株。经过PCR和PCR-Southern blot检测，转基因阳性植株为转为再生植株总数的89.45%。目前，虫试、Southern blot及Western blot正在进行之中。

Major histocompatibility complex class I involvement in the rejection of allogeneic erythrocytes in rainbow trout (Oncorhynchus mykiss)

Major histocompatibility complex genes are thought to be involved in allogeneic graft rejection but not many reports are available on their functional analysis in fish. Analysis of available sequences of MHC genes suggests functions in antigen presentation similar to those found in higher vertebrates. In mammals, the MHC class I and class II molecules are major determinants of allogeneic graft rejection due to their polymorphism in conjunction with their antigen presenting function. In fish, MHC class H molecules are found to be involved in rejection of allogeneic scale grafts. The present study was designed to investigate the involvement of MHC class I molecules in allograft rejection. Erythrocytes were collected from donors of rainbow trout expressed different class MHC class I alleles, stained with two dyes, mixed and grafted to the recipients that were of the same sibling group as the donors. The grafts were rejected by allogeneic recipients and the MHC class I linkage group was the major determinant for the rejection.

The role of vibration and drainage in femoral impaction bone grafting.

Vibration is commonly used in civil engineering applications to efficiently compact aggregates. This study examined the effect of vibration and drainage on bone graft compaction and cement penetration in an in vitro femoral impaction bone grafting model with the use of 3-dimensional micro-computed tomographic imaging. Three regions were analyzed. In the middle and proximal femoral regions, there was a significant increase in the proportion of bone grafts with a reciprocal reduction in water and air in the vibration-assisted group (P < .01) as compared with the control group, suggesting tighter graft compaction. Cement volume was also significantly reduced in the middle region in the vibration-assisted group. No difference was observed in the distal region. This study demonstrates the value of vibration and drainage in bone graft compaction, with implications therein for clinical application and outcome.

Improved suppression of circulating complement does not block acute vascular rejection of pig-to-rhesus monkey cardiac transplants

At present, acute vascular rejection (AVR) remains a primary obstacle inhibiting long-term graft survival in the pig-to-non-human primate transplant model. The present study was undertaken to determine whether repetitive injection of low dose Yunnan-cobra venom factor (Y-CVF), a potent complement inhibitor derived from the venom of Naja kaouthia can completely abrogate hemolytic complement activity and subsequently improve the results in a pig-to-rhesus monkey heterotopic heart transplant model. Nine adult rhesus monkeys received a heterotopic heart transplant from wild-type pigs and the recipients were allocated into two groups: group 1 (n = 4) received repetitive injection of low dose Y-CVF until the end of the study and group 2 (n = 5) did not receive Y-CVF. All recipients were treated with cyclosporine A (CsA), cyclophosphamide (CyP) and steroids. Repetitive Y-CVF treatment led to very dramatic fall in CH50 and serum C3 levels (CH50 < 3 units/C3 remained undetectable throughout the experiment) and successfully prevented hyperacute rejection (HAR), while three of five animals in group 2 underwent HAR. However, the continuous suppression of circulating complement did not prevent AVR and the grafts in group 1 survived from 8 to 13 days. Despite undetectable C3 in circulating blood, C3 deposition was present in these grafts. The venular thrombosis was the predominant histopathologic feature of AVR. We conclude that repetitive injection of low dose Y-CVF can be used to continuously suppress circulating complement in a very potent manner and successfully prevent HAR. However, this therapy did not inhibit complement deposition in the graft and failed to prevent AVR. These data suggest that using alternative pig donors [i.e. human decay accelerating factor (hDAF)-transgenic] in combination with the systemic use of complement inhibitors may be necessary to further control complement activation and improve survival in pig-to-non-human primate xenotransplant model.

TMVA, a novel GPIb-binding protein, significantly prevents platelet microthrombi formation and prolongs discordant cardiac xenograft survival

In xenotransplantation, donor endothelium is the first target of immunological attack. Activation of the endothelial cell by preformed natural antibodies leads to platelet binding via the interaction of the glycoprotein (GP) Ib and von Willebrand factor (vWF). TMVA is a novel GPIb-binding protein purified from the venom of Trimeresurus mucrosquamatus. In this study, the inhibitory effect of TMVA on platelet aggregation in rats and the effect on discordant guinea pig-to-rat cardiac xenograft survival were investigated. Three doses (8, 20 or 40 mug/kg) of TMVA were infused intravenously to 30 rats respectively. Platelet aggregation rate was assayed 0.5, 12, and 24 h after TMVA administration. Wister rats underwent guinea pig cardiac cervical heterotopic transplantation using single dosing of TMVA (20 mug/kg, i.v., 0.5 h before reperfusion). Additionally, levels of TXB2 and 6-keto-PGF(1alpha) within rejected graft tissues were determined by radioimmunoassay. Treatment with TMVA at a dose of 20 or 40 mug/kg resulted in complete inhibition of platelet aggregation 0.5 h after TMVA administration. Rats receiving guinea pig cardiac xenografts after TMVA therapy had significantly prolonged xenograft survival. Histologic and immunopathologic analysis of cardiac xenografts in TMVA treatment group showed no intragraft platelet microthrombi formation and fibrin deposition. Additionally, the ratio of 6-keto-PGF(1alpha) to TXB2 in TMVA treatment group was significantly higher than those in control group. We conclude that the use of this novel GPIb-binding protein was very effective in preventing platelet microthrombi formation and fibrin deposition in a guinea pig-to-rat model and resulted in prolongation of xenograft survival. The increased ratio of PGI(2)/TXA(2) in TMVA treatment group may protect xenografts from the endothelial cell activation and contribute to the prolongation of xenograft survival.

Hierarchical orientation of crystallinity by block-copolymer patterning and alignment in an electric field

Electron and hole conducting 10-nm-wide polymer morphologies hold great promise for organic electro-optical devices such as solar cells and light emitting diodes. The self-assembly of block-copolymers (BCPs) is often viewed as an efficient way to generate such materials. Here, a functional block copolymer that contains perylene bismide (PBI) side chains which can crystallize via π-π stacking to form an electron conducting microphase is patterned harnessing hierarchical electrohydrodynamic lithography (HEHL). HEHL film destabilization creates a hierarchical structure with three distinct length scales: (1) micrometer-sized polymer pillars, containing (2) a 10-nm BCP microphase morphology that is aligned perpendicular to the substrate surface and (3) on a molecular length scale (0.35-3 nm) PBI π-π-stacks traverse the HEHL-generated plugs in a continuous fashion. The good control over BCP and PBI alignment inside the generated vertical microstructures gives rise to liquid-crystal-like optical dichroism of the HEHL patterned films, and improves the electron conductivity across the film by 3 orders of magnitude. © 2013 American Chemical Society.

Long term peripheral nerve regeneration using a novel PCL nerve conduit.

The gold standard in surgical management of a peripheral nerve gap is currently autologous nerve grafting. This confers patient morbidity and increases surgical time therefore innovative experimental strategies towards engineering a synthetic nerve conduit are welcome. We have developed a novel synthetic conduit made of poly ε-caprolactone (PCL) that has demonstrated promising peripheral nerve regeneration in short-term studies. This material has been engineered to permit translation into clinical practice and here we demonstrate that histological outcomes in a long-term in vivo experiment are comparable with that of autologous nerve grafting. A 1cm nerve gap in a rat sciatic nerve injury model was repaired with a PCL nerve conduit or an autologous nerve graft. At 18 weeks post surgical repair, there was a similar volume of regenerating axons within the nerve autograft and PCL conduit repair groups, and similar numbers of myelinated axons in the distal stump of both groups. Furthermore, there was evidence of comparable re-innervation of end organ muscle and skin with the only significant difference the lower wet weight of the muscle from the PCL conduit nerve repair group. This study stimulates further work on the potential use of this synthetic biodegradable PCL nerve conduit in a clinical setting.

Non-destructive optical characterization of phase separation in bulk heterojunction organic photovoltaic cells

The dithiophene donor-acceptor copolymers that are bridged either with carbon (C-PCPDTBT) or silicon atoms (Si-PCPDTBT) belong to a promising family of materials for use in photoactive layers for organic photovoltaic cells (OPVs). In this work, we implement the non-destructive Spectroscopic Ellipsometry technique in the near infrared to the far ultraviolet spectral region in combination with advanced theoretical modeling to investigate the vertical distribution of the C-PCPDTBT and Si-PCPDTBT polymer and fullerene ([6,6]-phenyl C71-butyric acid methyl ester - PC70BM) phases in the blend, as well as the effect of the polymer-to-fullerene ratio on the distribution mechanism. It was found that the C-PCPDTBT:PC70BM blends have donor-enriched top regions and acceptor-enriched bottom regions, whereas the donor and acceptor phases are more homogeneously intermixed in the Si-PCPDTBT:PC70BM blends. We suggest that the chemical incompatibility of the two phases as expressed by the difference in their surface energy, may be a key element in promoting the segregation of the lower surface phase to the top region of the photoactive layer. We found that the increase of the photoactive layer thickness reduces the polymer enrichment at the cathode, producing a more homogeneous phase distribution of donor and acceptor in the bulk that leads to the increase of the OPV efficiency. © 2014 Elsevier B.V.

含苯胺五聚体嵌段共聚物的合成及生物医学应用

随着高分子材料在生物医学领域研究的深入，电活性高分子以其特有的化学和物理性质，受到国内外学者的广泛重视。电活性高分子，尤其是聚苯胺，在空气中稳定，导电性较高，能可逆氧化还原且无细胞毒性，因而在生物医学领域得到了较为广泛的应用，包括生物传感器、组织工程支架、用于粘附蛋白质或DNA的基质及电化学控制释放药物的电极等。但是限制聚苯胺在体内应用的最大问题是它的不可降解和不可吸收性，长期存在体内会造成炎症反应，需要二次手术取出。为了解决这个问题，我们设计合成了一系列新颖的共聚物材料，采用可生物降解的小分子量脂肪族聚酯（包括聚乳酸和聚己内酯）和电活性的苯胺五聚体利用N,N'-二环己基碳二亚胺（DCC）缩合法形成嵌段共聚物，得到了具有电活性的可生物降解材料，并证明这些共聚物材料具有很好的生物相容性，在电刺激条件下能够促进细胞的生长和分化，有望作为支架材料在神经组织工程中得到应用。我们还利用聚乙二醇和苯胺五聚体合成具有电活性的三嵌段共聚物，这种三嵌段共聚物在稀溶液中能够自组装成电刺激和pH响应敏感的球形胶束，而在浓溶液中能够形成具有微米尺寸的“沙漏”型组装体。三嵌段共聚物的这些独特的性质使其在药物控制释放等领域有着广阔的应用潜能。

二氧化碳共聚物结构和性质的研究

二氧化碳共聚反应制备的聚亚丙基碳酸酷（PPC）可完全生物降解并且无污染。该产物玻璃化温度较低，非结晶性，耐热性稍差，从而限制了它的应用。本文制备了乙基纤维素（EC），纤维素（Cell），聚乙烯醇（PVA）和聚对乙烯基苯酚（PVPh）与PPC的共混物，利用DSC，TGA，WAXD，皿，SEM和XPS研究它们的结构和性质。对于马来酸配封端的PPC（MAPPC）／EC共混物，富EC组分显示热致液晶性。向MAPPC混入EC后，提高了MAPPC的热分解温度。IR结果显示MAPPC的拨基氧和EC的经基氢之间存在弱的相互作用。WAXD表明用胆街型液晶EC稀释MAPPC，链间距和非晶相尺寸增加。DSC指出全部组成范围内PPC与纤维素，PPC与PVPh相容。FTIR证明PPC的氧官能团和纤维素的轻基以及PPC的氧官能团和PVPh的轻基之间存在氢键作用。XPS阐明PPC碳酸醋基的碳氧单键和碳氧双键的氧原子分别与纤维素的经基、PVPh轻基之间产生相互作用。用Dsc研究了聚乙烯醇（PVA）与苯磺酞氯封端的PPC（BsPPc）共混物熔融结晶行为。根据平衡熔点和组分间相互作用参数x12，表明熔融态共混物的相容性和组分间的氢键作用。使用修正Lauritzen-Hoffman表达式讨论了初始阶段结晶速率常数与温度的依赖性。首次获得纯PVA及其PVA／BSPPC共混物的折叠表面和侧向表面自由能以及链折叠功。

星形和多嵌生物降解聚合物

本论文针对聚ε-己内酯（PCL）为代表的可生物降解脂肪族聚酷亲水性差等缺点，通过共聚反应，在聚酷中引入了亲水性的聚环氧乙烷链段（PEO），制备了具有四臂星形结构的聚己内酯一聚环氧乙烷两亲性共聚物。通过氨基酸N-拨酸配开环反应制备了含有聚氨基酸链段的两亲性三嵌段共聚物，该结构共聚物与脂肪族聚酷均聚物相比具有更好的组织相容性。本论文的创新性和主要研究结果如下：1．通过采用以二乙基锌为催化剂，季戊四醇为引发剂的引发体系，合成了具有端轻基结构的四臂星形聚ε-己内酯。聚合产物的分子量可以通过改变单体与引发剂之比进行有效的控制。通过GPC、IR、NMR等测试手段证实聚合物分子链具有星形结构。2．以四臂星形聚ε-己内酯为大分子引发剂、二乙基锌为催化剂，通过引发环氧乙烷的开环反应制备了具有星形结构的嵌段共聚物。根据各种测试分析的实验结果确定了共聚物的链结构。3．DSC和WAXD的分析表明，星形嵌段共聚物由于核心部分为PCL，其结晶能力受到了处于外部的PEO链段的限制。当PEO足够长时，将观察不到PCL段的结晶。4．运用蔡钾和乙睛为活性聚合引发体系，通过分步加入环氧乙烷和ε-己内酯两种 单体的方法合成了带有睛端基的两亲性嵌段共聚物。5．采用把／碳和Raney-Nickel混合催化体系，成功地将端睛基PCL-PEO加氢还原为端氨基共聚物。6．以端氨基PCL-PEO为大分子引发剂引发γ-苄基-L-谷氨酸NCA开环聚合制备了带有聚氨基酸醋链段的两亲性共聚物。

两亲性三嵌段共聚物在选择性稀溶液中的自组装及应用

本论文主要研究了ABA和ABC型两亲性三嵌段共聚物在选择性稀溶液中的自组装行为，得到了多种形态新颖、结构复杂多样的胶束，研究了这些复杂胶束的形成过程，探讨了影响胶束形态的各种因素并通过适当的方法对胶束形态进行调控。研究了聚乙烯基毗陡（P4VP）／聚苯乙烯（PS）三嵌段共聚物P4VP-b-PS-b-P4VP在二氧六环／水中的自组装行为，成功得到了嵌段共聚物环状胶束，并通过实验研究了环状胶束的形成过程。结果表明，胶束形态依赖于退火时间的长短。随着退火时间的延长，胶束结构从棒状过渡到环形结构。以实验结果为基础提出了环状胶束形成的新的机理，即囊泡塌陷形成环。同时，通过改变实验条件还得到了一些新型的环状复合结构，如环套环形、鸟状、哑铃形、戒指形、网络状等结构，并得到了与计算机模拟一致的结果。通过不同的方法对ABA型三嵌段共聚物（P4VP-b-PS-b-P4VP）在选择性溶液中的自组装胶束形态进行调控：首先，详细研究了P4VP-b-PS-b-P4VP在不同的共溶剂中的自组装行为。结果表明通过单纯改变共溶剂的性质可以很方便地调节胶束的形态，得到了球、棒、囊泡等结构。并用混合溶剂的方法得到了长度和直径可控的纳米线胶束。同时，通过加入第二种选择性溶剂（核层嵌段PS的选择性溶剂甲苯）的方法使形成胶束的核层嵌段在胶核中的伸展程度增加，从而使胶束形态发生转变。其次，研究了加入表面活性剂十五烷基苯酚（PDP）以构建分子间氢键来调节P4VP-b-PS-b-P4VP的胶束形态。结果表明，通过调节PDP的加入量可以使胶束形态发生从球到棒，到网络状、再到囊泡结构的转变。通过实验对比系统地研究了PDP的加入对胶束形态转变的影响，提出了相应的形态转变机理。再次，研究了不同分子量的嵌段共聚物之间共混及共聚物与均聚物共混对胶束形态的影响。结果表明加入亲油嵌段的均聚物对共聚物胶束形态影响非常明显，胶束形态与加入的均聚物的分子量及加入量直接相关。同时得到了一些新形态的胶束，如海绵状、笼子状等。共聚物共混的研究结果表明：通过两种不同分子量的共聚物共混可以得到这两种共聚物胶束的过渡态结构。用共聚物混合的方法还可以得到一些具有生物模拟性的胶束结构，如乌贼状、章鱼状等。这加深了人们对囊泡的形成机理及各种胶束形态之间形态转变的认识。P4VP-b-PS-b-P4VP通过在二氧六环／水中的自组装形成了囊泡，结果表明囊泡的尺寸依赖于初始状态下共聚物在共溶剂中的浓度及退火时间。除得到常规的球形囊泡外，还得到一些非球形囊泡，如长条形、三角形、项链形等囊泡结构。结合计算机模拟的方法研究了囊泡的形成机理，发现这些不同结构的囊泡的形成是由于初始状态下密度涨落所引起的。研究了实验中经常出现的各种胶束形态共存现象的原因，发现体系中亚稳态的存在是多形态共存的重要原因之一。通过聚苯乙烯一左聚乙烯基毗睫一左聚氧乙烯（PS一b一PZVP一b一PEO）在THF／水中的二次自组装首次得到了一种具有生物模拟性的巨大的节状蠕虫胶束（SWM）。研究发现，SWM是由重复单元盘状结构和丝状结构相连组成的。最令人吃惊的是这种SWM与自然界中的一些生命体如蛆叫、蛹、昆虫类的幼虫结构非常相似。通过对SWM形成过程中的中间态胶束结构的深入研究发现SWM是由球形胶束通过二次自组装形成的。SWM的形成过程可以分为三个阶段：ABC三嵌段共聚物先组装形成球形结构；这些球型结构粘连在一起形成梭形的中间结构；这些梭状中间结构中的球经过重组和重新调整各嵌段的排布最终形成SWM。用所得到的嵌段共聚物胶束为模板，采用无电沉积的方法成功制备了各种形态的金属一有机高分子纳米复合材料。用简单的方法还得到了导电金属金一银的双金属纳米结构材料。这些纳米结构材料在微电子器件等领域有潜在应用价值。以上研究结果丰富了人们对嵌段共聚物在选择性介质中自组装行为的理解，为人们提供了对生物材料自组装本质的理解的依据。这在两亲性分子在溶液中自组装的基础研究方面以及基于这些自组装形态而构建结构及功能更复杂的纳米结构材料等方面都有一定的意义。

半结晶性嵌段共聚物自组装与薄膜微相分离

本论文以半结晶性的PLLA-b-PS为研究对象，主要研究两个方面的问题。首先研究聚合物结晶对嵌段共聚物在稀溶液中的自组装行为的影响。在此基础上，研究薄膜状态下，聚合物结晶与微相分离之间的相互作用。首先，我们系统地研究了PLLA-b- PS在不同溶剂中的自组装结构。通过调节溶剂选择性由中性向弱选择性和选择性改变，PLLA-b-PS分别形成类旋节图案，松散的胶束结构和典型的胶束核壳结构。使用混合溶剂，实现了从结晶性的球形胶束向结晶性的片状胶束的转变。标度理论分析和实验结果表明，溶剂与胶束结晶核心之间的界面能的增加是发生这一转变的主要原因。为了研究薄膜中的微相分离与结晶之间的相互作用，我们比较了三种薄膜条件下的相分离与结晶过程。均匀平坦的PLLA-b-PS薄膜是旋节不稳定的，在几以上时，分子链发生微相分离，形成旋节图案，表面诱导分子链的伸展有序化过程促使PLLA分子链发生折叠结晶，形成非经典的亚稳态凸出结构，相分离层间距增大50％。结晶过程为一级动力学。在薄膜中引入成核剂时，PLLA在几以上即开始结晶，同时实现了PLLA与P3之间的相分离，薄膜的旋节不稳定性得到了松弛。结晶使薄膜收缩，形成大量的裂纹。在PLLA熔点以上时，以裂纹为核，在薄膜中形成大量的孔洞。孔洞的生长为经典的动力学过程。我们利用自组装方法在薄膜中引入半结晶性的开放的纳米棒。在几以上时，PLLA在纳米棒中发生结晶，诱导薄膜中的分子链向纳米棒迁移，从而在薄膜中形成孔洞结构。同时，薄膜中的未结晶分子链被表面和界面诱导取向，这种取向结构利于PLLA结晶，结晶被加速，从而孔洞的生长也被加速。也就是说，结晶与孔洞的生长相互促进。在相分离薄膜中，PLLA的结晶形态与结晶温度有关。To＜TgPS时，结晶被束缚在相结构中，相分离结构不变；TgPs＜Tc＜Tm以及Tc→Tm时，结晶对相结构有一定的破坏，相分离片层结构的层间距增大，薄膜收缩，形成大量的裂纹和缺陷。在180℃时，PLLA形成不稳定的晶体结构；PLLA与PS之间的相分离强度被减弱，在线张力作用下，岛状结构的相对高度大幅度增加；在岛状结构的边缘，线张力驱使部分分子链穿越已有的相结构，形成多层岛状结构。