Design and synthesis of donor-acceptor type compatibilizer based on polythiophene and fullerene for enhancing the performance of organic solar cells

이제욱 서울대학교 대학원 2010 국내박사

Structure and Dynamics of Particle Forming Diblock Copolymer Melts and their Blends

Mueller, Andreas J ProQuest Dissertations & Theses University of Minn 2022 해외박사(DDOD)

소속기관이 구독 중이 아닌 경우 오후 4시부터 익일 오전 9시까지 원문보기가 가능합니다.

Complex micellar packings which mimic transition-metal alloy crystal structures known as Frank Kasper phases have been serendipitously identified in a range of soft matter since the early 1990s. The set of known soft Frank Kasper (FK) phases presently includes A15, σ, C14, C15, and one instance of Z alongside closely related dodecagonal quasicrystals (DDQCs). These structures boast low symmetry unit cells containing ≥ 7 particles of ≥ 2 distinct shapes and sizes– a notable deviation from the two particles of a single type populating the canonical body centered cubic (BCC) lattice. The discovery of Frank Kasper phases in ostensibly simple diblock copolymer melts cemented the universality of this behavior across soft matter and triggered widespread reevaluation of the phase behavior of particle-forming diblock copolymers aimed at establishing far-reaching geometric principals underlying the formation of these low symmetry phases. This work addresses these concerns from two directions. First core-homopolymer/diblock (A′/AB) blends where diblock particle cores are swollen with core-block homopolymer were demonstrated to form thermodynamically stable Frank Kasper phases, even in diblock systems that do not form them in the bulk. These ideas were subsequently expanded towards low-molecular weight A′/AB blends, where A′ molecular weight was tuned to dictate AB diblock chain packing in the blend, and thus the ensuing impact on particle packing lattice symmetry. These works established simple A′/AB blending as a general strategy for forming Frank Kasper phases. Notably, these experiments were originally designed in analogy to a surfactant system, underscoring the universality of the geometry of complex phase formation across different types of system.The second thrust of this work focused on the nature of the metastable DDQC, which often forms in advance of equilibrium Frank Kasper phases– hence many Frank Kasper phases are known as quasicrystalline approximants. Initially, this involved establishing the conditions for DDQC formation in a crystalline amorphous poly(ethylene oxide)-block-poly(2-ethylhexyl acrylate) OA diblock copolymer with a minority poly(ethylene oxide) fraction. The OA diblock was demonstrated to undergo breakout crystallization at sufficiently low temperatures, erasing the melt particle-packing microstructure. Melting the semicrystalline state below the order-disorder transition of the diblock enable direct access to a supercooled glass-like packing of particles, which offered a platform from which a DDQC could nucleate. Quenching to the same temperature from the thermally disordered state (above the order-disorder transition) instead BCC to nucleate, which directly transitioned to σ, underscoring the requirement of disorder for the formation of the DDQC.Last, X-ray photocorrelation spectroscopy (XPCS) experiments were performed on a binary blend of a pair of poly(styrene)-block-poly(1,4-butadiene) diblock copolymers which forms DDQC at short anneal times, before ultimately transitioning to σ. These XPCS measurements revealed a wealth of dynamic information wherein σ apparently displays faster grain dynamics compared to DDQC at the same temperature in the same system, attributed to the differing grain structures of each phase.

Synthesis of block copolymer micelles for supracolloidal chains and surface-functionalized nanoparticles

이상화 Seoul National University 2016 국내박사

Self-assembled nano-building blocks into controlled superstructures is of significant importance in technological applications as well as of great interest in basic science because cooperative electronic, photonic, and magnetic properties of individual nano-objects are determined by the collective interactions in their ensembles. In particular, uniform nanoparticles of metals, semiconductors, oxides, and polymers have been assembled into supracolloidal assemblies upon the controlled attraction between nanoparticles. Especially, patchy nanoparticles have been employed as colloidal building blocks which can be effectively polymerized into linear supracolloidal chains. Colloidal particles with well-ordered patches have been developed mainly for mimicking the valency in an atomic structure to demonstrate an artificial atom in the large scale. However, colloidal particles with multivalent patches have not been utilized for controlling branching or crosslinking. In addition, it would not be trivial to synthesize colloidal patchy particles smaller than 100 nm. In this thesis, we focus on the controlled branching and eventual crosslinking in supracolloidal chains by introducing well-defined trifunctional patchy micelles. Three patches in the micelles worked as the distinct parts for crosslinking as well as branching, analogues to multifunctional groups in classical gelation of small molecular monomers. These branched and crosslinked supracolloidal chains were well compared with long linear chains only with bifunctional micelles. Furthermore, we carried real visual images on branching and crosslinking in chain-like structures which cannot be directly imaged in conventional gelation of small multifunctional monomers. We also demonstrate that diblock copolymer micelles can be used as surface-functionalized particles and they can be coated with Ag or TiO2 nanoparticles without surface modification. We obtained dopamine-functionalized diblock copolymers which were synthesized by the reversible addition fragmentation chain transfer polymerization and followed by the post-polymerization modification. By dissolving this amphiphilic diblock copolymer in water, spherical micelles with the dopamine-functionalized coronas were induced, which are essentially equivalent to polymeric particles with dopamine-functionalized surface. Chapter 1 gives a brief overview of the self-associating characteristics of diblock copolymers, which assemble into micelles with soluble coronas and insoluble cores in a selective solvent for one of the blocks. The structure and dimension of block copolymer micelles can be precisely tuned by the molecular weight of polymers and the weight ratio of the blocks. These diblock copolymer micelles can be potentially employed as nano-sized polymeric colloids. The synthesis and post-polymerization modification of block copolymers for functionalization is also introduced. In Chapter 2, we demonstrate that controlled branching and eventual crosslinking in supracolloidal chains by introducing well-defined trifunctional patchy micelles. Uniform micelles having three patches were induced from core-crosslinked micelles of diblock copolymers. Three patches in the micelles served as functional groups for crosslinking as well as branching in supracolloidal polymerization with bifunctional patchy micelles. Thus, by the addition of trifunctional micelles, supracolloidal chains showed branches originated only from the trifunctional units and were eventually crosslinked into the network structure, in sharp contrast to long linear chains of bifunctional patchy micelles. Formation of crosslinked supracolloidal chains of patchy micelles was understood by the classical gelation theory. We also delivered visual images on branching and crosslinking in chain-like structures which cannot be directly imaged in conventional gelation of small multifunctional monomers. In Chapter 3, we describe that diblock copolymer micelles can be used as surface-functionalized particles and they can be coated with Ag or TiO2 nanoparticles without surface modification. We first obtained dopamine-functionalized diblock copolymers which were synthesized by the reversible addition fragmentation chain transfer polymerization and followed by the post-polymerization modification. By dissolving this amphiphilic diblock copolymer in water, spherical micelles with the dopamine-functionalized coronas were induced, which are essentially equivalent to polymeric particles with dopamine-functionalized surface. Thus, without additional surface functionalization, we were able to directly decorate these particles with Ag and TiO2 nanoparticles due to the dopamine functionality on their surface.

Controlled organization of colloidal nanomaterials with block copolymer micelles

김정희 서울대학교 대학원 2015 국내박사

Colloidal nanoparticles based on organic and inorganic materials have been the core elements of nanotechnology because they exhibit unique photonic, electronic and stimuli-sensitive properties depending on their sizes, shapes and chemical characteristics. Beyond the synthesis and utilization of single colloids, the organization of colloidal nanoparticles while controlling their combination and spatial distribution in a system is attracting much interest to achieve unusual nano- and micro-structures and practical applications of the functionalities of colloidal nanoparticles. The organization of colloidal nanoparticles includes the assembly of colloids with the attachment of building units and the arrangement of nanoparticles into periodic arrays. By employing colloidal nanoparticles as nanoscale building blocks, organized colloidal superstructures can be assembled depending on the interaction between colloidal nanoparticles. The controlled assembly of colloidal nanoparticles enables the production of nature-mimic hierarchical structures and periodic structures with photonic properties. The arrangement of colloids on a solid substrate offer the control of the interparticle distance which is essential to utilize the functionalities of colloidal nanoparticles in device applications as the photonic and electronic properties of colloidal nanoparticles are modified by the interparticle coupling, which is affected by the distance between the colloids. Nanostructures of arranged colloidal nanoparticles on the nanoscale can also be applied as nanomasks and nanotemplates for the fabrication of the nanostructures of other materials. Various colloidal nanoparticles, such as metal nanoparticles and polymeric colloids, serve as building blocks for the construction of organized colloidal structures. Given that block copolymers self-assemble into nanometer-sized micelles with soluble corona blocks and insoluble core blocks in a solvent which is selective for one of the blocks, block copolymer micelles can be utilized as a type of polymeric colloidal nanoparticles. In addition, block copolymer micelles can be applied as templates for the creation of organized metal and inorganic colloidal nanomaterials. In this thesis, we focus on the development of organized structures of colloidal nanoparticles through the use of diblock copolymer micelles. Diblock copolymer micelles, as colloidal building blocks, assemble into colloidal superstructures with controlled morphologies in a solution. We also demonstrate the utilization of diblock copolymer micelles as colloidal templates for the synthesis and arrangement of metal nanoparticles on solid substrates. Metal nanoparticle arrays created from a thin film of diblock copolymer micelles were further combined with fluorophore-encapsulating diblock copolymer micelles to control the interaction between the metal colloids and light emitters through micellar nanostructures, suggesting the potential application for the effective control of the fluorescence. In chapter 1, we offer an overview of the self-associating characteristics of diblock copolymers, which assemble into micelles with soluble coronas and insoluble cores in a selective solvent for one of the blocks. The structure and dimension of block copolymer micelles can be precisely tuned by the molecular weight of polymers and the weight ratio of the blocks. These diblock copolymer micelles can be potentially employed as nano-sized polymeric colloids. Since diblock copolymer micelles can include functional substances, e.g. organic dyes and inorganic precursors, in their core blocks, they are beneficial as colloidal templates for arranging and organizing other colloidal nanomaterials in ordered arrays. In chapter 2, we demonstrate supracolloidal polymer chains of diblock copolymer micelles. With a diblock copolymer composed of a polar block and a non-polar block, typical spherical micelles were initially obtained in a selective solvent for a non-polar block. We cross-linked the polar core of diblock copolymer micelles and then made the solvent preferable to the core block but still compatible with the corona block. The cross-linked core was not dissolved by the favorable solvent but was exposed to the solvent when the corona was rearranged into two separate patches. In other words, typical spherical micelles were converted to colloidal micelles with the corona reorganized into two non-polar patches and the central core directly exposed to the solvent. With the reorganized micelles as colloidal monomers, we were able to polymerize their linear supracolloidal chains by increasing the polarity of the solvent. Furthermore, we applied the same protocol to diblock copolymers of a lower molecular weight and produced small colloidal monomers which were then combined with large colloidal monomers for the synthesis of supracolloidal random and block copolymers. In chapter 3, we synthesize a diblock copolymer, consisting of one block which allows the synthesis of nanoparticles and another block which is selectively removable, by means of the reversible addition-fragmentation chain transfer (RAFT) polymerization. Using a selective solvent for each block, we produced two types of spherical micelles with an inverse position of two blocks, that is, the core of the nanoparticle-synthesizable block and the corona of the removable block and vice versa. We then coated single layers of these two micelles onto substrates, which were successfully employed as templates for the arrangement of spherical gold nanoparticles and their ring-like configuration over a large area. In chapter 4, we utilize diblock copolymer micelles to organize metal nanoparticle arrays on a solid substrate which can be applied for the plasmon-coupled fluorescence. A single layer of diblock copolymer micelles containing metal precursors in the core blocks was coated onto a solid substrate. The nanostructures of the micellar arrays of diblock copolymers were transferred to metal nanoparticle arrays by the reduction of metal precursors and the elimination of the polymers. The distance between the metal nanoparticles was controlled by the intermicellar distance in a single layer of diblock copolymer micelles. These metal nanoparticle arrays were applied as a seed substrate for the growth of larger metal nanoparticles with controlled size and interparticle distances. Diblock copolymer micelles were also used for the isolation of organic fluorophores in the micellar cores. A thin film of diblock copolymer micelles with organic dyes was combined with metal nanoparticle arrays to verify the strategy of metal-coupled fluorescence enhancement.

Structure and Dynamics of Micelle-Forming Asymmetric Diblock Copolymer Chains

Chawla, Anshul ProQuest Dissertations & Theses University of Minn 2022 해외박사(DDOD)

소속기관이 구독 중이 아닌 경우 오후 4시부터 익일 오전 9시까지 원문보기가 가능합니다.

Experiments on micelle-forming asymmetric diblock copolymer melts have shown the existence of a liquid-like state of micelles at temperatures greater than the order-disorder transition temperature (ODT). These micelles have been hypothesized to appear at an even greater temperature called the critical micelle temperature (CMT). The regime between the CMT and ODT, called the disordered micellar regime, has been known to affect the formation of many exotic phases like the Frank-Kasper and the Laves phases due to its slow dynamics. Self-Consistent Field Theory (SCFT), one of the most commonly employed theoretical tools, only predicts the appearance of micelles in stationary and periodic configurations, and hence is incapable of capturing the disordered micellar regime. Some previous theoretical studies do provide predictions of the structural properties of the disordered micelles, however, these studies used SCFT predictions of free energies of isolated micelles to approximate the free energy of disordered micelles.We have used coarse-grained classical molecular dynamics to simulate melts of asymmetric diblock copolymer chains having a minority block volume fraction, f = 0.125. At high χN, where χ is the Flory-Huggins interaction parameter and N is the degree of polymerization, SCFT predicts the formation of ordered micellar phases for this volume fraction. Our simulations show the existence of a disordered micellar regime for χN above the (χN)scfodt, where (χN)scfodt is the value of χN corresponding to the ODT predicted from SCFT. We study melts having two significantly different invariant degree of polymerization, N = 960 and 3820, that span the disordered homogenous phase, disordered micellar regime, and the ordered body-centered cubic (BCC) phase.The first part of this thesis pertains to analyzing the evolution of the structure of these melts as a function of χN. By using a cluster identification algorithm, we show that micelle-like clusters appear at a CMT with the appearance being much more sudden for the higher N simulations. Moreover, micelles appear when χN is near (χN)scfodt. We also show that the signature of the presence of disordered micelles in scattering experiments (SAXS and SANS) arises at a somewhat higher χN as compared to (χN)scfodt. Comparisons of the free energy derivative, peak wavenumber, micelle aggregation number and the free chain fraction obtained from simulations with these quantities calculated from SCFT show close agreement, thus emphasizing similarities in the structure of the disordered micelles and the ordered micelles predicted by SCFT at the same χN. Analysis of the shape of the identified clusters also reveal a rapid formation/breaking of bridges between micelles present in both disordered and ordered phases.The latter part of this thesis considers the dynamics of these melts, namely single chain diffusion and structural relaxation. Signatures of the sudden appearance of micelles at the CMT is also reflected in the analysis of the dynamic properties as a sudden slowdown in the molecular relaxation and an even more significant slow down in the structural relaxation. We measure the rate at which polymers are expelled from micelles, and relate this to the polymer diffusivity.

Fragmentation of Block Copolymer Micelles in Ionic Liquids

Early, Julia Taylor ProQuest Dissertations & Theses University of Minn 2021 해외박사(DDOD)

소속기관이 구독 중이 아닌 경우 오후 4시부터 익일 오전 9시까지 원문보기가 가능합니다.

Spatial arrangement of quantum dots directed by nanostructures of block copolymers

채승용 Seoul National University 2016 국내박사

구형의 금속, 산화금속 및 반도체로 이루어진 나노입자는 벌크 상태는 볼 수 없는 독특한 특성을 가지고 있기 때문에 차세대 소재로써 연구되어 왔다. 이와 같은 구형 나노입자는 최근 제조 기술의 발전으로 균일한 크기와 형태로 제조가 가능해짐에 따라, 용액상 혹은 고체상에서의 입자 간 배열에 대한 관심이 증폭되고 있으며, 특히 배열된 입자 간 상호작용에 의하여 개개의 나노입자와는 다른 특성이 관찰되기 때문에 이를 이용하려는 연구가 활발히 진행되고 있다. 양자점의 결정 구조의 제조가 보고된 이래로 단일 혹은 이중 이상의 나노입자로 이루어진 다양한 형태의 밀집구조가 연구되었으며, 이제는 단순한 밀집구조를 넘어 복잡한 구조의 나노입자 배열이 연구되고 있다. 나노입자의 배열은 전자 빔 혹은 광자 리소그래피에 의한 하향식 방법으로 얻어질 수 있다. 하지만 일반적인 리소그래피 기술에 의한 배열은 기판 위의 2차원적 평면에서만 유효하다는 한계를 가지고 있다. 반면 자기조립 구조를 가지는 물질에 의해 형성된 나노구조를 형판으로 하여 나노입자를 배열 할 수 있다면 상향식으로 1차원, 2차원뿐만 아니라 3차원의 정렬된 배열을 구현할 수 있기 때문에 하향식의 한계를 극복할 수 있는 대안으로 부각되고 있다. 특히 둘 혹은 그 이상의 다른 화학적 구조를 가진 고분자 사슬로 구성된 블록공중합체는 고체상 혹은 용액상에서 자기조립에 의한 장거리 질서를 가진 정렬된 나노구조를 형성하기 때문에 나노입자의 배열 제어를 위한 이상적인 재료이다. 본 연구는 이중블록공중합체 나노구조를 통하여 양자점의 공간적 배열을 제어하는 데에 목적을 두었다. 블록공중합체 나노구조를 따라 양자점이 배열되기 위해서는 이중블록공중합체의 한 블록과 양자점 간의 선택적인 상용성이 요구된다. 이러한 상용성을 부여하기 위하여 이중블록공중합체의 특정 블록 혹은 양자점의 표면에 강한 상호 작용을 가능케 하는 기능기를 도입하였다. 이를 통해 양자점과 블록공중합체로 이루어진 복합 필름 내에서 블록공중합체 나노구조에 의한 양자점의 배열의 구현되었다. 또한 용액 상에서도 양자점이 이중블록공중합체 마이셀의 코어에 선택적인 도입이 이루어졌으며, 이중블록공중합체 마이셀이 형성하는 선형의 콜로이드 고분자 사슬을 통해 배열이 이루어졌다. 더 나아가 유기 형광체 혹은 다른 종류의 양자점과의 조합을 통하여 블록공중합체 나노구조에 의해 제어된 다중 형광특성을 구현할 수 있었다. 제 1장에서는 블록공중합체의 고체상 혹은 용액상에서 형성하는 자기조립 나노구조에 대하여 개괄적으로 서술하였다. 기능성 블록공중합체를 위한 합성 방법 및 후중합 반응에 관하여 간략히 소개하였다. 제 2장에서는 블록공중합체와 양자점으로 구성된 복합체 필름 내에서 블록공중합체의 판상형 나노구조를 따라 제어된 양자점의 배열을 다루었다. 블록공중합체가 양자점을 위한 고분자 매트릭스로서 배열을 할 수 있도록 하기 위하여, 반응성의 블록을 가진 블록공중합체를 합성하고, 후중합 반응에 의해 양자점과 강한 결합을 할 수 있는 티올기로 기능화하였다. 스핀코팅에 의하여 제조된 다양한 두께의 복합체 박막 내에서 용매 증기 어닐링을 통하여 배향이 제어된 판상형의 나노구조를 유도하였으며, 나노구조를 따라 양자점이 효과적으로 배열되었음을 확인하였다. 또한 용매 캐스팅에 의해 제조된 수마이크로 두께의 프리스탠딩 필름에서도 무작위적 배열을 가진 판상형 나노구조 내에 양자점이 효과적인 배열을 하였음을 확인하였다. 제 3장에서는 2장에서 다루었던 티올 기능화된 블록공중합체와 양자점에 더하여 유기형광체로 기능화된 블록공중합체를 혼합하여, 블록공중합체 나노구조 내에 이종의 형광체를 동시 도입 및 배열하는 연구를 다루었다. 티올 기능화된 블록공중합체와 형광 기능화된 블록공중합체는 다른 종류의 기능기를 소량 가지고 있지만 화학적으로 동일한 기본적인 구조를 가지도록 하여 혼합 시 거대 상분리 없이 하나의 나노구조를 형성하도록 하였다. 2장에서 사용된 블록공중합체의 반응성 블록에 후중합 반응을 통하여 유기형광체를 결합하였으며, 이를 가지고 제조된 박막 내에서 유기 형광체로 기능화된 판상형 나노구조가 동일하게 형성됨을 확인하였다. 양자점과 각각의 기능화된 블록공중합체가 혼합된 복합체 박막 필름에서 형성된 판상형 나노구조의 한 블록 내에 양자점과 유기형광체가 동시에 선택적으로 도입되었으며, 나노구조 내에 제한되어 수나노 거리 안에 위치한 양자점과 유기형광체 사이의 FRET (Fluorescent Resonance Energy Transfer) 현상을 관찰하였다. 제 4장에서는 용액상에서 형성된 블록공중합체 마이셀을 단량체로 하여 형성된 콜로이드 고분자 사슬에 의한 양자점의 배열에 관하여 서술하였다. 녹색과 적색의 발광을 하는 양자점들은 먼저 표면의 개질을 통해 코어를 형성하는 블록과 수소결합이 가능하도록 하였으며, 이를 통해 블록공중합체 마이셀의 가교된 코어에 효과적으로 도입하였다. 양자점이 도입된 구형의 마이셀은 용매의 극성 조절을 통하여 2 개의 패치를 가진 이방성의 콜로이드 구조로 변형되며, 추가적인 용매의 극성 조절을 통해 선형의 고분자 사슬을 형성함을 확인하였다. 또한 두 가지의 양자점이 각각 도입된 마이셀을 패치 입자 혹은 콜로이드 사슬 단계에서 혼합하는 방법을 통해 녹색과 적색의 발광을 동시에 가지는 랜덤 혹은 블록공중합 형태의 콜로이드 고분자를 제조하였으며, 이를 초고해상도 광학 현미경 중 하나인 SIM (structured illumination microscopy)를 통하여 확인하였다. Metal, oxide, and semiconductor nanoparticles have attracted considerable attention due to their unique properties, which are different from those of their respective bulk materials. Advances in the synthesis of spherical nanoparticles with uniform size have also made it possible to extend this difference by creating ensembles of nanoparticles within assemblies in solution or solids. Single and binary crystal structures of nanoparticles with long-range order over hundreds of microns have already been achieved using this approach; thus, considerable effort is now being directed toward going beyond these close-packed structures to produce tailored structures of spatially arranged nanoparticles. Such an arrangement can be obtained using “top-down” techniques such as e-beam and photo lithography; however, conventional lithographic techniques are only effective with solids on a substrate. In contrast, “bottom-up” self-assembly provides a platform for generating 1-D, 2-D, and 3-D ordered arrays. Here, block copolymers composed of two or more chemically different polymers provide an ideal template for directing the arrangement of nanoparticles, as they have a self-assembled nanostructure over macroscopic distances in solid and solution. In this thesis, we focus on the directed spatial arrangement of quantum dots (QDs) by block copolymer nanostructures, which requires selective compatibility between the two. To this end, we introduced functionalities into specific copolymer blocks or QDs to improve their interaction, thereby allowing QDs to be arranged along the nanostructure of a block copolymer in a composite film, or encapsulated and linearly arranged by block copolymer micelles in solution. Furthermore, by combining organic fluorophores with different kinds of QDs, multiple-fluorescence controlled by the nanostructure of the block copolymer was achieved. Chapter 1 gives a brief overview of the nanostructure of block copolymers when self-assembled in a solid and in solution. The synthesis and post-polymerization modification of block copolymers for functionalization is also introduced. In Chapter 2, we demonstrate that the spatial arrangement of QDs can be directed by the lamellar nanostructure of a functional block copolymer in a composite film. As it is the polymer matrix that directs the arrangement of QDs, post-polymerization modification is used to create a diblock copolymer containing a reactive block with thiol functionalities that can interact with QDs. Thin films of this block copolymer are fabricated with various thicknesses by spin-coating, with solvent annealing being used to create perpendicular and parallel lamellar nanostructures for the selective arrangement of QDs. A free-standing film with a randomly orientated lamellar nanostructure is also fabricated by solvent-casting, comparison with which reveals that the absorbance and photo luminescent properties of the QDs are preserved in all of the composite films. In Chapter 3, we describe how the simultaneous arrangement of two fluorophores is achieved using the nanostructure of a block copolymer by blending the thiol-functionalized block copolymer used in Chapter 2 with an organic fluorophore-anchored block copolymer. This has the same basic chemical structure for each block, but has slightly different functional moieties in one of its blocks so that it can be incorporated into the same nanostructure. Organic fluorophores are also introduced along the reactive block using the post-polymerization modification method demonstrated in Chapter 2, producing a lamellar nanostructures was also confirmed. Thus, functionalized block copolymers, QDs and organic fluorophores are all simultaneously arranged into the lamellar nanostructure of a block copolymer. Fluorescence resonance energy transfer (FRET) is observed between the QDs and organic fluorophores which were concurrently confined in the nanoscale domains. The linear arrangement of QDs under the direction of the supracolloidal polymer chain of a block copolymer micelle in solution is presented in Chapter 4. Here, we encapsulated green- or red-emitting QDs in the diblock copolymer micelles which have cross-linked core, and then induced supracolloidal polymer chains by sequentially changing the polarity of the solvent. Since each chain contained ether green- or red-emitting QDs, fluorescent supracolloidal chains functionalized with QDs were successfully produced. Furthermore, by combining the micellar monomers into monomeric and polymeric states, we were able to achieve supracolloidal random and block chains with green and red emissions, as observed directly by structured illumination microscopy.

Synthesis of pH-sensitive PAM-DET dendrimer and PEO-PMAA diblock copolymer and its application to gene/drug delivery

진근우 서울대학교 대학원 2011 국내박사