Polymer Tubes by Rolling of Polymer Bilayers

Kumar, Kamlesh; Nandan, Bhanu; Luchnikov, Valériy; Zakharchenko, Svetlana; Ionov, Leonid; Stamm, Manfred

doi:10.1557/proc-1272-oo01-09

Cited by 4 publications

(5 citation statements)

References 14 publications

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“…The radii of curvature of the self-curling structures depend on the thickness of the component films and their relative swelling ratios. Polymeric tubes with diameters as small as 100 nm have been reported [98]. Additionally, the wall thickness of the tubes can be controlled by varying the thickness of the polymer thin films, the number of turns can be altered by varying the lateral dimensions, and the tubes can also be patterned.…”

Section: Self-folding Of Polymeric Containersmentioning

confidence: 99%

Self-folding polymeric containers for encapsulation and delivery of drugs

Fernandes

Gracias

2012

Advanced Drug Delivery Reviews

258

182

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Self-folding broadly refers to self-assembly processes wherein thin films or interconnected planar templates curve, roll-up or fold into three dimensional (3D) structures such as cylindrical tubes, spirals, corrugated sheets or polyhedra. The process has been demonstrated with metallic, semiconducting and polymeric films and has been used to curve tubes with diameters as small as 2 nm and fold polyhedra as small as 100 nm, with a surface patterning resolution of 15 nm. Self-folding methods are important for drug delivery applications since they provide a means to realize 3D, biocompatible, all-polymeric containers with well-tailored composition, size, shape, wall thickness, porosity, surface patterns and chemistry. Self-folding is also a highly parallel process, and it is possible to encapsulate or self-load therapeutic cargo during assembly. A variety of therapeutic cargos such as small molecules, peptides, proteins, bacteria, fungi and mammalian cells have been encapsulated in self-folded polymeric containers. In this review, we focus on self-folding of all-polymeric containers. We discuss the mechanistic aspects of self-folding of polymeric containers driven by differential stresses or surface tension forces, the applications of self-folding polymers in drug delivery and we outline future challenges.

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Section: Self-folding Of Polymeric Containersmentioning

confidence: 99%

Self-folding polymeric containers for encapsulation and delivery of drugs

Fernandes

Gracias

2012

Advanced Drug Delivery Reviews

258

182

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“…6,15 Structural parameters also govern the particle mean deposition distance. Another potential approach is to employ anisotropic bilayers composed of inorganic [27][28][29] or organic 30 layers with contrasting properties either intrinsically or externally. 7,8,16 Various fabrication methods of hollow nanotubes have been developed using a range of materials, including organic polymers 17 and metal oxides.…”

Section: Introductionmentioning

confidence: 99%

“…Self-assembly processes must deal with polydispersity of the tubes. Another potential approach is to employ anisotropic bilayers composed of inorganic [27][28][29] or organic 30 layers with contrasting properties either intrinsically or externally. Because the layer anisotropy governs the curvature, i.e., the size of the internal cavity, control of the internal cavity of such bilayers is accomplished by varying the constituents.…”

Section: Introductionmentioning

confidence: 99%

Self-rolled nanotubes with controlled hollow interiors by patterned grafts

2015

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By patterning surface grafts, we propose a simple and systematic method to form tubular structures for which two-dimensional grafted sheets are programmed to self-roll into hollow tubes with a desired size of the internal cavity. The repeating pattern of grafts utilizing defect sites causes anisotropy in the surface-grafted nanosheet, which spontaneously transforms into a curved secondary architecture and, thus, becomes a potential tool with which to form and control the curvature of nanotubes. In fact, the degree and the type of graft defect allow control of the internal cavity size and shape of the resulting nanotubes. By performing dissipative particle dynamics simulations on coarse-grained sheets, we found that the inner cavity size is inversely proportional to the graft-defect density, the difference in the graft densities between the two surface sides of the layer, regardless of whether the defects are patterned or random. While a random distribution of defects gives rise to a non-uniform local curvature and often leads to twisted tubes, regular patterns of graft defects ensure uniform local curvature throughout the sheet, which is important to generate monodisperse nanotubes. At a low graft-defect density, the sheet-to-tube transformation is governed by the layer anisotropy, which induces spontaneous scrolling along the long edge of the sheet, resulting in short tubes. Thus, the curve formation rate and the cavity diameter are independent of the pattern of the graft defects. At a high graft-defect density, however, the scroll direction owing to the graft pattern may conflict with that due to the layer anisotropy. To produce monodisperse nanotubes, two factors are important: (1) a graft-defect pattern parallel to the short edge of the layer, and (2) a graft-defect area wider than half of the graft coil length.

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“…Self‐folding, a deterministic self‐assembly process, provides a desirable strategy for creating 3D microscale structures for 3D sensing, 3D metamaterials, microrobots, drug delivery, cell cultures, cell encapsulation, and microscale chemical container applications . Self‐assembly of 3D microscale structures can be accomplished by different trigger mechanisms including magnetic force‐driven self‐assembly, electric force‐driven assembly, pneumatic force‐driven assembly, differential stress‐driven assembly, shape memory assembly, and surface tension‐driven assembly . Among these assembly processes, the self‐folding using a hinge joining two panels is normally triggered by forces induced within the hinge materials to convert 2D panels into 3D structures.…”

mentioning

confidence: 99%

“…Among these assembly processes, the self‐folding using a hinge joining two panels is normally triggered by forces induced within the hinge materials to convert 2D panels into 3D structures. Physical or chemical property changes of the hinges are required to generate the forces that lift up the panels . In order to generate the physical or chemical property changes, external heat energy has been mainly used.…”

mentioning

confidence: 99%

Remotely Controlled Microscale 3D Self‐Assembly Using Microwave Energy

Liu

Schauff

Joung

et al. 2017

Adv Materials Technologies

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for self-assembly. The heat energy is usually applied from an external source, such as a hotplate [51] or hot liquid bath, [52][53][54][55] which requires direct contact with the heat source. Another way to induce changes in the physical/chemical property is to apply environmental (e.g., pH or ionic strinength) changes to solvent-sensitive hinge materials. [20,56,57] Physical/chemical reactions occur when solvents are in contact with the hinge materials, triggering the self-assembly. However, a major drawback of these assemblies is that the direct contact of heat energy sources or chemicals with the hinge materials critically limits its applications and reduces the manipulative capability of the selfassembly because the heat sources are not controllable, and the environment around the microstructures is not accessible in many practical situations. Moreover, direct heat energy sources, such as a hotplate or a hot liquid bath, usually have a high thermal mass, leading to a thermal lag (or time delay) from when the input energy is controlled to when the 2D structures begin to assemble. Thus, the assembling process cannot be precisely controlled using such methods.Recently, remote-controlled self-assembly has been developed using microwave energy to avoid direct contact between heat sources and structures and to achieve precise control of self-folding. [58] The microwave energy causes the temperature of the millimeter-scale hinge materials (i.e., graphene ink and metal nanoparticles) to increase and trigger self-folding. The remotely applied microwave energy leads to quickly and accurately controlled folding of polymer sheets, which are ideal for time sensitive applications and remotely controlled applications. However, the advanced self-assembly technique using microwave energy needs to be further investigated in order to create 3D self-assembled structures for various applications, including 3D sensors, carriers, and microbots. Also, the ability to build 3D structures on a microscale is necessary because microscale self-assembly allows for the realization of 3D structures that can be used for diverse 3D terahertz sensors [54] and biomedical devices designed for in vivo operation. [10][11][12]56,57] In addition, the development of complex 3D microstructures and microbots requires self-assembly having the ability to conduct different configurations (controllable multiple folding angles of each frame) simultaneously during a self-assembly process. Multiple configurations can be achieved under uniform stimulation by applying different hinge materials, [59] using angle-lock A novel, remotely controlled assembly process is developed to create microscale, self-assembled 3D structures using remote-controlled microwave energy. A nanometer thick chromium (Cr) film absorbs electromagnetic microwaves and generates heat energy, which induces reflow of polymeric hinges. This leads to self-assembly of microscale 3D cubic structures. Since this assembly process does not require direct contact with a heat source or chemicals, micro...

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Polymer Tubes by Rolling of Polymer Bilayers

Cited by 4 publications

References 14 publications

Self-folding polymeric containers for encapsulation and delivery of drugs

Self-folding polymeric containers for encapsulation and delivery of drugs

Self-rolled nanotubes with controlled hollow interiors by patterned grafts

Remotely Controlled Microscale 3D Self‐Assembly Using Microwave Energy

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