智能涂料制备方法探索与应用

智能涂料是近几年在新型特种功能涂料基础上发展起来的.本文主要对其制备方法、类别及应用进行了详细论述.智能涂料的制备可以从聚合物膜、颜料及制作工艺等方面入手,其中创造具有"开关"性质且依赖于外部环境的刺激/响应聚合物膜的设计最为重要,它关系到膜的形成和膜表面性质,是涂料智能化的关键所在.在合成方法上,活性/可控自由基聚合技术、表面接枝技术和层层自组装工艺等已经应用于智能聚合物膜的制备;另外,纳米技术应用于涂料,也是智能涂料另一制备方法,因其某些超强性能而被视为智能涂料的初级阶段.目前,整个智能涂料的发展还基本处于以纳米技术为基础的初级阶段,其中进展较大的品种有:自清洁、抗菌、防腐、隐身、发光、磁性等对光、电、磁、温、湿、压敏感的涂料,而以智能聚合物膜为基础的高层次智能涂料还基本处于研究开发阶段.     

Retracted: Control of Nanoparticle Release by Membrane Composition for Dual-Responsive Nanocapsules

Stimulus-responsive polymeric nanocapsules usable as cell mimics can be engineered to precisely control cargo release. This work reports the release behavior of post-loaded nanoparticles through permeable membranes of stable pH and temperature dual-responsive polymeric nanocapsules (CP1, CP2, and CP3) with the same membrane thickness but different membrane composition, prepared by layer-by-layer assembly and surface-initiated single electron transfer living radical polymerization, respectively. These nanocapsules differ in their tunable membrane permeability for post-loaded nanoparticles as protein mimics, tailored by pH and temperature stimuli. Release mechanisms are dominated by membrane composition, such as polyelectrolyte multilayer membrane for CP1, pure cationic membrane for CP2, and valve-like functions for CP3. Thus, one can postulate the main locations of post-loaded protein mimics in the different nanocapsules. Understanding the post-loading and diffusion mechanism of nanoparticles through permeable membranes in cell mimics paves the way for the construction of new “smart” synthetic protocells with control over the exchange of bioactive nanoparticles between different compartments.     

Bioreducible Nanocapsules Prepared from the Self‐assembly of Branched Polymer in Nanodroplet

Though great attention has been paid in constructing well‐defined nano‐structures via the self‐assembly of amphiphilic macromolecules, the self‐assembly of non‐amphiphilic macromolecules in nanodroplet has drawn less attention up to now. Recently, we prepared a temperature‐responsive PEG‐based branched polymer with disulfide bonds in its backbone via reversible addition–fragmentation chain transfer (RAFT) polymerization of 2‐(2‐methoxyethoxy) ethyl methacrylate, oligo(ethylene glycol) methacrylate, and N,N′‐cystamine bisacrylamide. Subsequently, we loaded the branched polymer into nanodroplets, and have found that the self‐assembly behaviors of this branched poly­mer in the nanodroplet are different from those in common solution. Bioreducible nanocapsules with tunable size can easily formed in nanodroplet even at high concentration.

     

基于抗菌肽的智能型抗菌涂层研究进展

抗菌肽作为一种高效、广谱、不致细菌耐药性的抗菌物质受到科研人员的广泛关注。 在生物材料表面制备抗菌肽基涂层是减少器械相关细菌感染的有效途径。 然而传统抗菌肽释放型涂层受限于抗菌肽存储量,抗菌时效短;抗菌肽直接固定涂层易遭受死细菌对杀菌性能的掩蔽。 另外,生物材料使用场景的多变性和复杂性,强烈要求材料的正常服役和抗感染性能具有高度可调控性。 将刺激响应聚合物与现有的抗菌策略相结合,并通过精巧的设计来构建智能型抗肽涂层平台,对于获取优异的抗菌特性和丰富体系的使用场景具有重要意义。 本文综述了智能型抗菌肽涂层的研究进展,阐述了构建释放型和非释放型涂层的主要策略,分析了刺激响应聚合物在抗菌体系中的作用及角色,探讨了智能抗菌肽涂层在正常服役和感染应对阶段的功能转换设计,并对智能型抗菌肽涂层的未来发展做出展望。     

Sustained and Controlled Release of Volatile Precursors for Chemical Vapor Deposition of Graphene at Atmospheric Pressure

Precursors and catalysts play vital roles in chemical reactions. Considerable efforts have been devoted to the investigation of catalysts for graphene growth by chemical vapor deposition in recent years. However, there has been little research on precursors because of a lack of innovation in term of creating a controllable feeding method. Herein, we present a novel sustained and controlled release approach, and develop a convenient, safe, and potentially scalable feeding system with the assistance of matrix materials and a simple portable feeder. As a result, a highly volatile liquid precursor can be fed accurately to grow large-area, uniform graphene films with optimal properties. This feeding approach will further benefit the synthesis of other two-dimensional materials from various precursors.     

Thermosensitive Microneedles Capable of On Demand Insulin Release for Precise Diabetes Treatment

As a novel painless and minimally invasive transdermal drug delivery method, microneedles have solved the challenges of microbial infection and tissue necrosis associated with multiple subcutaneous injections in patients with diabetes. However, traditional soluble microneedles cannot switch drug release on and off according to the patient's needs during long-term use, which is one of the most critical elements of diabetes treatment. Herein, an insoluble thermosensitive microneedle (ITMN) that can control the release of insulin by adjusting the temperature, enabling the precise treatment of diabetes is designed. Thermosensitive microneedles are produced by in situ photopolymerization of the temperature-sensitive compound N-isopropylacrylamide with the hydrophilic monomer N-vinylpyrrolidone, which is encapsulated with insulin and bound to a mini-heating membrane. ITMN are demonstrated to have good mechanical strength and temperature sensitivity, can release significantly different insulin doses at different temperatures, and effectively regulate blood glucose in type I diabetic mice. Therefore, the ITMN provides a possibility for intelligent and convenient on-demand drug delivery for patients with diabetes, and when combined with blood glucose testing devices, it has the potential to form an integrated and precise closed-loop treatment for diabetes, which is of great importance in diabetes management.     

Microencapsulation of a Crop Protection Compound by Initiated Chemical Vapor Deposition

In this work, initiated chemical vapor deposition (iCVD) has been employed as a one‐step liquid‐free process combining polymerization and coating for the encapsulation of 3D non‐planar substrates. Coatings have been applied using iCVD specifically to encapsulate microparticles of a highly water‐soluble crop protection compound (CPC) for controlled release. Release behavior has been compared among different coatings synthesized using different iCVD processing conditions, including varying degrees of polymer hydrophobicity, continuous and pulsed deposition, and crosslinking. iCVD has been found to provide tunable synthesis of hydrophobic, crosslinked polymers with control over mass diffusivity, and coating thickness for enhancing barrier properties.     

Controlled Release of the Dithiocarbamate Ligand From A Polypyrrole Polymer. A Basis For On-Line Electrochemicalycontrolled Derivatisation

Abstract

The development of a novel on-line derivatisation scheme is described. the scheme involves use of a conducting polymeric material into which the derivatising agent is incorporated. the properties of the polymer enable electrochemical controlled release of the reagent into flowing solutions.     

利用超分子接枝聚合物体系制备具有pH响应能力的高分子囊泡及其在药物控制释放方面的应用

利用自由基聚合的链转移反应,制备了以羧基为端基的聚(N-异丙基丙烯酰胺)(PNIPAM-COOH),然后以该聚合物作为亲水的侧链,利用其羧端基和聚(4-乙烯基吡啶)(PVPy)疏水主链上的吡啶基团间的相互作用,在共溶剂DMF中形成超分子两亲接枝聚合物体系,在上述体系中逐滴加入水可以使其通过自组装形成高分子囊泡.通过控制PVPy与PNIPAM-COOH的质量比在1～3之间,可以控制囊泡尺寸在130～330nm之间.由于囊泡中含有吡啶基团,因而该囊泡具有pH敏感性.以日落黄为药物模型,以这些pH敏感性囊泡作为药物载体,通过调节环境的pH值可以实现对药物的控制释放.     

Micro-Encapsulation and Antifouling Coatings: Development of Poly(lactic acid) Microspheres Containing Bioactive Molecules

Summary: Environmental legislation compels marine paints companies to develop non toxic antifouling coatings respecting ecosystems. In this work, biodegradable polymers are used to conceive delivery systems with a lifetime of many months. For this purpose, chlorhexidine was encapsulated in poly(L-lactide) microspheres and incorporated in antifouling formulations. The characterization (encapsulation yield, surface morphology, particle size) and antibacterial activity (bacteriostatic and bactericidal effects) of microspheres were carried out by using scanning electronic (SEM) and confocal laser scanning microscopies (CLSM). The results indicate a good ability of loaded microspheres to be formulated even though an excellent activity against selected marine bacteria is conserved. This is a promising approach to develop biodegradable antifouling paints based on non toxic molecules and bioactive surfaces.     

聚合物结构对包膜缓释肥缓释性能的影响

研发和使用缓控释肥能有效解决普通肥料利用率低以及由于化肥使用过量而引起的环境问题。聚合物包膜型缓控释肥是缓控释肥中的一种,影响其缓释性能的因素如环境因素、包膜厚度、加工工艺等,前人已研究较多。聚合物结构对于缓释性能的影响也很重要,而这方面研究较少。本文主要讨论了聚合物结晶性、分子亲疏水性、分子链柔顺性、交联等结构因素对缓释性能的影响。深入研究聚合物结构对缓释性能的影响有助于缓控释材料的创新;能为聚合物包膜材料的设计、聚合物缓控释肥的研发及生产提供一定的理论依据。     

Biomimetic Bottlebrush Polymer Coatings for Fabrication of Ultralow Fouling Surfaces

Demand for long‐lasting antifouling surfaces has steered the development of accessible, novel, biocompatible and environmentally friendly materials. Inspired by lubricin (LUB), a component of mammalian synovial fluid with excellent antifouling properties, three block polymers offering stability, efficacy, and ease of use were designed. The bottlebrush‐structured polymers adsorbed strongly on silica surfaces in less than 10 minutes by a simple drop casting or online exposure method and were extremely stable in high‐salinity solutions and across a wide pH range. Antifouling properties against proteins and bacteria were evaluated with different techniques and ultralow fouling properties demonstrated. With serum albumin and lysozyme adsorption <0.2 ng cm^?2, the polymers were 50 and 25 times more effective than LUB and known ultralow fouling coatings. The antifouling properties were also tested under MPa compression pressures by direct force measurements using surface forces apparatus. The findings suggest that these polymers are among the most robust and efficient antifouling agents currently known.     

Synthesis of Breathing Metallopolymer Hollow Spheres for Redox‐Controlled Release

A convenient synthetic approach for the preparation of uniform metallopolymer‐containing hollow spheres based on 2‐(methacryloyloxy)ethyl ferrocenecarboxylate (FcMA) as monomer by sequential starved feed emulsion polymerization is described. Core/shell particles consisting of a noncrosslinked poly(methyl methacrylate) core and a slightly crosslinked ferrocene‐containing shell allows for the simple dissolution of core material and, thus, monodisperse metallopolymer hollow spheres are obtained. Since PFcMA is incorporated in the particle shell, herein investigated hollow spheres can be addressed by external triggers, i.e., solvent variation and redox chemistry in order to change the particle swelling capability. PFcMA‐containing core/shell particles and hollow spheres are characterized by transmission electron microscope (TEM), scanning electron microscopy, cryogenic TEM, thermogravimetric analysis, and dynamic light scattering in terms of size, size distribution, hollow sphere character, redox‐responsiveness, and composition. Moreover, the general suitability of prepared stimulus‐responsive nanocapsules for the use in catch‐release systems is demonstrated by loading the nanocapsules with malachite green as model payload followed by release studies.

     

One-pot synthesis of PDMAEMA nanocapsules for controlled release of hydrophobic cargo

In this work, poly((N,N-dimethyl amino)ethyl methacrylate) (PDMAEMA) homopolymers are synthesized using RAFT technique, which is then used as stabilizers to prepare miniemulsion droplets in a toluene/hexadecane(HD)/1,2-Bis-(2-iodoethyl)ethane(BIEE)/hydrophobic molecule/water mixture. Upon the reaction between BIEE and the stabilizers of miniemulsion droplets, the polymeric nanocapsules are formed and capable of encapsulating hydrophobic molecule in their oil core in one-step reaction. The release of hydrophobic cargo from the nanocapsules can be controlled by the variation of amount of surfactant (Tween®20) in the release medium and a long duration sustained release was achieved.     

Bio‐Orthogonal Polymer Coatings for Co‐Presentation of Biomolecules

Controlled presentation of biomolecules on synthetic substrates is an important aspect for biomaterials development. If the immobilization of multiple biomolecules is required, highly efficient orthogonal surface chemistries are needed to ensure the precision of the immobilization. In this communication, chemical vapor deposition (CVD) copolymerization is used to fabricate polymer coatings with controlled ratio of alkyne and pentafluorophenyl ester (Pfp‐ester) groups. Cyclic argine‐glycine‐aspartic acid (cRGD) adhesion peptide and epidermal growth factor (EGF) are immobilized through alkyne–azide cycloaddtion (“click” chemistry) and active ester–amine reaction, respectively. Cell studies with human umbilical vein endothelial cells (HUVEC) and A431 cell lines demonstrate the biological activity of the coimmobilized biomolecules.     

Development of Smart Polymer Microparticles through Suspension Polymerization for Treatment of Schistosomiasis

Schistosomiasis is a parasitic disease that affects millions of people, especially low‐income people, and is considered a major public health problem in underdeveloped countries. The drug used most often for the treatment of the disease is praziquantel (PZQ), which has a strong and characteristic bitter taste that makes treatment of children inconvenient. For this reason, the present work investigates the development of smart pH‐sensitive polymer microparticles produced through suspension polymerizations to be used as vehicles for the controlled release of praziquantel in the body. The microparticles are produced through copolymerization of methyl methacrylate and the cationic comonomers diethylaminoethyl methacrylate or dimethylaminoethyl methacrylate. The obtained results indicate that microparticles with sizes in the range of 10–1100 µm can be formed successfully, allowing high PZQ encapsulation efficiencies (>80%). Zeta potential analyses and drug release assays confirm the pH‐sensitive responses of the cationic copolymers, leading to effective release of PZQ (around 80% in pH 1.2) in acidic media that simulate the organic fluids present in the stomach.     

A Mathematical Study on Effect of 2-Hydroxyl Ethyl Acrylate on Controlled Drug Diffusion from Smart Hydrogels Based on Poly(acrylamide-co-hydroxy ethyl acrylate-co-acrylic acid)

A series of poly (AM-co-HEA-co-AA) hydrogels have been synthesized and characterized by varying 2-hydroxy ethyl acrylate (HEA) content in the range of 0–16.22% in feed. The swelling ratio of resulting hydrogels was drastically decreased 10 times, i.e., from 101.12 to 9.23 in an almost linear fashion; but the dimensional stability of these hydrogels was increased significantly from 5 to 46 days with increasing HEA content. The hydrogels exhibited Smart nature in varying pH (2–10), temperature (15–65°C), ionic strength of NaCl solution (0.1M-1.5M), and different cation chloride salt solution having same ionic strength (0.1M). The swelling mechanism was shifted from non-Fickian to Fickian (at pH 2–7), super case to non-Fickian (at pH 10) with increasing HEA content. The controlled release of model drug (salicylic acid) from these hydrogels was investigated using early-time, late-time and Etters diffusion models and compared with the experimental data. It was observed that early model doesn't fit, but Etter and late-time model fitted excluding the initial phase. However, it was also observed that with increasing HEA content, the applicability of Etter's model improved, and for 16.22% HEA containing hydrogel Etters model was fitted in the full range, indicating that by varying hydrogel composition, the diffusion characteristics can be altered.     

Solid Lipid Nanoparticles Produced via a Coacervation Method as Promising Carriers for Controlled Release of Quercetin

Quercetin is a poorly water-soluble flavonoid with many benefits to human health. Besides the natural food resources that may provide Quercetin, the interest in delivery systems that could enhance its bioavailability in the human body has seen growth in recent years. Promising delivery system candidates are represented by Solid Lipid Nanoparticles (SLNs) which are composed of well-tolerated compounds and provide a relatively high encapsulation efficiency and suitable controlled release. In this study, Quercetin-loaded and negatively charged Solid Lipid Nanoparticles were synthesized based on a coacervation method, using stearic acid as a core lipid and Arabic Gum as a stabilizer. Samples were qualitatively characterized by Dynamic light scattering (DLS), Zeta Potential, Surface infrared spectroscopy (FTIR-ATR), and Time of flight secondary ion mass spectrometry (ToF-SIMS). Encapsulation efficiency, drug release, and antioxidant effect against ABTS^•+ were evaluated in vitro by UV–VIS spectrophotometry.